1
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Wu XT, Yang C, Xi JS, Shi C, Du FS, Li ZC. Enabling Closed-Loop Circularity of "Non-Polymerizable" α, β-Conjugated Lactone Towards High-Performance Polyester with the Assistance of Cyclopentadiene. Angew Chem Int Ed Engl 2024; 63:e202404179. [PMID: 38488293 DOI: 10.1002/anie.202404179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Indexed: 04/17/2024]
Abstract
Chemical recycling of polymers to monomers presents a promising solution to the escalating crisis associated with plastic waste. Despite considerable progress made in this field, the primary efforts have been focused on redesigning new monomers to produce readily recyclable polymers. In contrast, limited research into the potential of seemingly "non-polymerizable" monomers has been conducted. Herein, we propose a paradigm that leverages a "chaperone"-assisted strategy to establish closed-loop circularity for a "non-polymerizable" α, β-conjugated lactone, 5,6-dihydro-2H-pyran-2-one (DPO). The resulting PDPO, a structural analogue of poly(δ-valerolactone) (PVL), exhibits enhanced thermal properties with a melting point (Tm) of 114 °C and a decomposition temperature (Td,5%) of 305 °C. Notably, owing to the structural similarity between DPO and δ-VL, the copolymerization generates semi-crystalline P(DPO-co-VL)s irrespective of the DPO incorporation ratio. Intriguingly, the inherent C=C bonds in P(DPO-co-VL)s enable their convenient post-functionalization via Michael-addition reaction. Lastly, PDPO was demonstrated to be chemically recyclable via ring-closing metathesis (RCM), representing a significant step towards the pursuit of enabling the closed-loop circularity of "non-polymerizable" lactones without altering the ultimate polymer structure.
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Affiliation(s)
- Xiao-Tong Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
| | - Chun Yang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jian-Shu Xi
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
| | - Changxia Shi
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
| | - Fu-Sheng Du
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
| | - Zi-Chen Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry & Molecular Engineering, Peking University, Beijing, 100871, China
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2
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Sato M. Structural diversity of decalin forming Diels-Alderase. Biosci Biotechnol Biochem 2024:zbae040. [PMID: 38758077 DOI: 10.1093/bbb/zbae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
The Diels-Alder (DA) reaction, specifically referring to the [4 + 2] cycloaddition reaction in pericyclic reactions, is a process that forms two carbon-carbon covalent bonds in a single step via an electron ring transition state. Among the secondary metabolites produced by microorganisms, numerous compounds are biosynthesized through DA reactions, most of which are enzymatic. Our research group has discovered an enzyme named Diels-Alderase (DAase) that catalyzes the DA reaction in filamentous fungi, and we have been investigating its catalytic mechanism. This review describes the reported microbial DAase enzymes, with a particular focus on those involved in the construction of the decalin ring.
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Affiliation(s)
- Michio Sato
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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3
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Baruah B, Pegu CD, Deb ML. Indole as a Versatile Building Block in Cycloaddition Reactions: Synthesis of Diverse Heterocyclic Frameworks. Top Curr Chem (Cham) 2024; 382:18. [PMID: 38758483 DOI: 10.1007/s41061-024-00463-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 03/25/2024] [Indexed: 05/18/2024]
Abstract
Indole, a ubiquitous and structurally versatile aromatic compound, has emerged as a key player in the synthesis of diverse heterocyclic frameworks via cycloaddition reactions. These reactions are completely atom-economical and, hence, are considered as green reactions. This review article provides a comprehensive overview of the pivotal role played by indole in the construction of complex and biologically relevant heterocyclic compounds. Here we explore the chemistry of indole-based cycloadditions, highlighting their synthetic utility in accessing a wide array of heterocyclic architectures, including cyclohepta[b]indoles, tetrahydrocarbazoles, tetrahydroindolo[3,2-c]quinoline, and indolines, among others. Additionally, we discuss the mechanistic insights that underpin these transformations, emphasizing the strategic importance of indole as a building block. The content of this article will certainly encourage the readers to explore more work in this area.
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Affiliation(s)
- Biswajita Baruah
- Department of Chemistry, Pandu College, Guwahati, Assam, 781012, India.
| | - Choitanya Dev Pegu
- Department of Chemistry, Madhabdev University, Lakhimpur, Assam, 784164, India
| | - Mohit L Deb
- Advanced Research Centre and Department of Chemistry, University of Science and Technology Meghalaya, Ri-Bhoi, Meghalaya, 793101, India.
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Kirita K, Matsumoto H, Endo G, Hosokawa S. Total Syntheses of Borolithochromes A, D and G. Angew Chem Int Ed Engl 2024; 63:e202400586. [PMID: 38369567 DOI: 10.1002/anie.202400586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
Total syntheses of borolithochromes A, D and G, red pigments isolated from fossils of Jurassic putative red alga Solenopora jurassica, have been achieved. The benzo[gh]tetraphene skeletons of the borate ligands in these substances were constructed using Diels-Alder reactions of aryl dienes with naphthoquinone, followed by intramolecular Corey-Chaykovsky reactions. Complexation of these ligands with trimethyl borate generated homocomplexes, which upon sequential O-demethylation produced borolithochromes A and G. In the route to borolithochrome D, a heterocomplex was prepared by stepwise complexation of the ligands with 2-(dimethylamino)ethyl dimethyl borate. The strategy devised to accomplish the first total synthesis of borolithochromes A, D and G should be applicable to the preparation of other borolithochromes as well as spiroborates possessing two fused polycyclic aromatic ligands.
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Affiliation(s)
- Kanade Kirita
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan
| | - Hirotake Matsumoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan
| | - Gaku Endo
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan
| | - Seijiro Hosokawa
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan
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5
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Eggly AS, Otgontseren N, Roberts CB, Alwali AY, Hennigan HE, Parkinson EI. A Diels-Alder probe for discovery of natural products containing furan moieties. Beilstein J Org Chem 2024; 20:1001-1010. [PMID: 38711585 PMCID: PMC11070956 DOI: 10.3762/bjoc.20.88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
Natural products (NPs) are fantastic sources of inspiration for novel pharmaceuticals, oftentimes showing unique bioactivity against interesting targets. Specifically, NPs containing furan moieties show activity against a variety of diseases including fungal infections, and cancers. However, it is challenging to discover and isolate these small molecules from cell supernatant. The work described herein showcases the development of a molecular probe that can covalently modify furan moieties via a [4 + 2] Diels-Alder cycloaddition, making them easily identifiable on liquid chromatography-mass spectrometry (LC-MS). The molecular probe, which undergoes this reaction with a variety of furans, was designed with both a UV-tag and a mass tag to enable easy identification. The probe has been tested with a variety of purified furans, including natural products, methylenomycin furan (MMF) hormones, and MMF derivatives. Moreover, the molecular probe has been tested in crude supernatants of various Streptomyces strains and enables identification of MMFs.
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Affiliation(s)
- Alyssa S Eggly
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Namuunzul Otgontseren
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Carson B Roberts
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Amir Y Alwali
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Haylie E Hennigan
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Elizabeth I Parkinson
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47906, United States
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Wei XP, Wang XC, Ma T, Qiao XX, Li G, He Y, Zhao XJ. B(C 6F 5) 3/CPA-Catalyzed Aza-Diels-Alder Reaction of 3,3-Difluoro-2-Aryl-3H-indoles and Unactivated Dienes. Chemistry 2024:e202401008. [PMID: 38624085 DOI: 10.1002/chem.202401008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/17/2024]
Abstract
Here we report B(C6F5)3/CPA-catalyzed enantioselective aza-Diels-Alder reaction of 3,3-difluoro-2-Aryl-3H-indoles with unactivated dienes to access chiral 10,10-difluoro-tetrahydropyrido[1,2-a]indoles. This protocol allows the formation of pyrazole-based C2-quaternary indolin-3-ones with high enantioselectivities and regioselectivities. Moreover, gram-scale synthesis of the 10,10-difluoro-tetrahydropyrido[1,2-a]indole skeleton was successfully achieved without any reduction in both yield and enantioselectivity.
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Affiliation(s)
- Xing-Pin Wei
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Xin-Chun Wang
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Tao Ma
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Xiu-Xiu Qiao
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Ganpeng Li
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Yonghui He
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Xiao-Jing Zhao
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal, Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
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7
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Ishihara J. Progress in Lewis-Acid-Templated Diels-Alder Reactions. Molecules 2024; 29:1187. [PMID: 38474699 DOI: 10.3390/molecules29051187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
The synthesis of natural products with complicated architectures often requires the use of segments with functional groups that can be structurally transformed with the desired stereogenic centers. Bicyclic 𝛾-lactones have great potential as a suitable segment for natural product synthesis. However, the stereoselective construction of such functionalized bicyclic 𝛾-lactones is not as straightforward as one might expect. The template-mediated Diels-Alder reaction is one of the most powerful and versatile methods for providing bicyclic 𝛾-lactones with high regioselectivity and stereoselectivity. In this reaction, the diene is linked to the dienophile by a temporary tether, allowing the reaction to proceed efficiently, yielding a product that can be used for natural product synthesis. This review describes some important instances of the template-mediated Diels-Alder reaction and its application to the synthesis of biologically active compounds.
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Affiliation(s)
- Jun Ishihara
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 853-8521, Japan
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8
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Wang T, Gao D, Yin H, Zhao J, Wang X, Niu H. Kinetic Study of the Diels-Alder Reaction between Maleimide and Furan-Containing Polystyrene Using Infrared Spectroscopy. Polymers (Basel) 2024; 16:441. [PMID: 38337328 DOI: 10.3390/polym16030441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
The Diels-Alder (D-A) reaction between furan and maleimide is a thermally reversible reaction that has become a vital chemical technique for designing polymer structures and functions. The kinetics of this reaction, particularly in polymer bulk states, have significant practical implications. In this study, we investigated the feasibility of utilizing infrared spectroscopy to measure the D-A reaction kinetics in bulk-state polymer. Specifically, we synthesized furan-functionalized polystyrene and added a maleimide small-molecule compound to form a D-A adduct. The intensity of the characteristic absorption peak of the D-A adduct was quantitatively measured by infrared spectroscopy, and the dependence of conversion of the D-A reaction on time was obtained at different temperatures. Subsequently, the D-A reaction apparent kinetic coefficient kapp and the Arrhenius activation energy Ea,D-A were calculated. These results were compared with those determined from 1H-NMR in the polymer solution states.
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Affiliation(s)
- Tongtong Wang
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Dali Gao
- SINOPEC (Beijing) Research Institute of Chemical Industry Co., Ltd., Beijing 100013, China
| | - Hua Yin
- SINOPEC (Beijing) Research Institute of Chemical Industry Co., Ltd., Beijing 100013, China
| | - Jiawei Zhao
- SINOPEC (Beijing) Research Institute of Chemical Industry Co., Ltd., Beijing 100013, China
| | - Xingguo Wang
- SINOPEC (Beijing) Research Institute of Chemical Industry Co., Ltd., Beijing 100013, China
| | - Hui Niu
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
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9
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Alharbi HY, Alnoman RB, Aljohani MS, Al-Anazia M, Monier M. Synthesis and characterization of gellan gum-based hydrogels for drug delivery applications. Int J Biol Macromol 2024; 258:128828. [PMID: 38141700 DOI: 10.1016/j.ijbiomac.2023.128828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/01/2023] [Accepted: 12/13/2023] [Indexed: 12/25/2023]
Abstract
In this study, gellan gum (Gel) derivatives were allowed to interact via aqueous Diels-Alder chemistry without the need for initiators, producing a crosslinked hydrogel network that exhibited good potential as a drug carrier using tramadol as a drug model. Hydrogel conjugation was achieved by the synthesis of a maleimide and furan-functionalized Gel, and the pre- and post-gelation chemical structure of the resulting hydrogel precursors was fully investigated. Potential uses of the developed hydrogel in the pharmaceutical industry were also evaluated by looking at its gelation duration, temperature, morphologies, swelling, biodegradation, and mechanical characteristics. The Gel-FM hydrogels were safe, showed good antimicrobial activity, and had a low storage modulus, which meant that they could be used in many biochemical fields. The encapsulation and release of tramadol from the hydrogel system in phosphate-buffered saline (PBS) at 37 °C were investigated under acidic and slightly alkaline conditions, replicating the stomach and intestinal tracts, respectively. The in-vitro release profile showed promising results for drug encapsulation, revealing that the drug could safely be well-encapsulated in acidic stomach environments and released more quickly in slightly alkaline intestinal environments. This implies that the hydrogels produced could work well as polymers for specifically delivering medication to the colon.
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Affiliation(s)
- Hussam Y Alharbi
- Chemistry Department, Faculty of Science, Taibah University, Yanbu, Saudi Arabia.
| | - Rua B Alnoman
- Chemistry Department, Faculty of Science, Taibah University, Yanbu, Saudi Arabia
| | - Majed S Aljohani
- Chemistry Department, Faculty of Science, Taibah University, Yanbu, Saudi Arabia
| | - Menier Al-Anazia
- Department of Chemistry, Faculty of Science, University of Tabuk, Tabuk 71421, Saudi Arabia
| | - M Monier
- Chemistry Department, Faculty of Science, Taibah University, Yanbu, Saudi Arabia; Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt.
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10
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Carbonell-Blasco MP, Moyano MA, Hernández-Fernández C, Sierra-Molero FJ, Pastor IM, Alonso DA, Arán-Aís F, Orgilés-Calpena E. Polyurethane Adhesives with Chemically Debondable Properties via Diels-Alder Bonds. Polymers (Basel) 2023; 16:21. [PMID: 38201686 PMCID: PMC10780649 DOI: 10.3390/polym16010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Covalent adaptable networks (CANs) represent a pioneering advance in polymer science, offering unprecedented versatility in materials design. Unlike conventional adhesives with irreversible bonds, CAN-based polyurethane adhesives have the unique ability to undergo chemical restructuring through reversible bonds. One of the strategies for incorporating these types of reactions in polyurethanes is by functionalisation with Diels-Alder (DA) adducts. By taking advantage of the reversible nature of the DA chemistry, the adhesive undergoes controlled crosslinking and decrosslinking processes, allowing for precise modulation of bond strength. This adaptability is critical in applications requiring reworkability or recyclability, as it allows for easy disassembly and reassembly of bonded components without compromising the integrity of the material. This study focuses on the sustainable synthesis and characterisation of a solvent-based polyurethane adhesive, obtained by functionalising a polyurethane prepolymer with DA diene and dienophiles. The characterisation of the adhesives was carried out using different experimental techniques: nuclear magnetic resonance spectroscopy (NMR), Brookfield viscosity, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and T-peel strength testing of leather/adhesive/rubber joints to determine the adhesive properties, both before and after the application of external stimuli. The conversion of both the DA and retro-Diels-Alder (r-DA) reactions was confirmed by 1H-NMR. The adhesive properties were not altered by the functionalisation of the adhesive prepolymer, showing similar thermal resistance and good rheological and adhesive properties, even exceeding the most demanding technical requirements for upper-to-sole joints in footwear. After the application of an external thermal stimuli, the bonded materials separated without difficulty and without damage, thus facilitating their separation, recovery and recycling.
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Affiliation(s)
- María Pilar Carbonell-Blasco
- Footwear Technology Centre, Campo Alto Campo, Elda, 03600 Alicante, Spain; (M.A.M.); (C.H.-F.); (F.A.-A.); (E.O.-C.)
| | - María Alejandra Moyano
- Footwear Technology Centre, Campo Alto Campo, Elda, 03600 Alicante, Spain; (M.A.M.); (C.H.-F.); (F.A.-A.); (E.O.-C.)
| | - Carlota Hernández-Fernández
- Footwear Technology Centre, Campo Alto Campo, Elda, 03600 Alicante, Spain; (M.A.M.); (C.H.-F.); (F.A.-A.); (E.O.-C.)
| | - Francisco J. Sierra-Molero
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), Faculty of Sciences, University of Alicante, P.O. Box 99, 03080 Alicante, Spain; (F.J.S.-M.); (I.M.P.); (D.A.A.)
| | - Isidro M. Pastor
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), Faculty of Sciences, University of Alicante, P.O. Box 99, 03080 Alicante, Spain; (F.J.S.-M.); (I.M.P.); (D.A.A.)
| | - Diego A. Alonso
- Department of Organic Chemistry, Institute of Organic Synthesis (ISO), Faculty of Sciences, University of Alicante, P.O. Box 99, 03080 Alicante, Spain; (F.J.S.-M.); (I.M.P.); (D.A.A.)
| | - Francisca Arán-Aís
- Footwear Technology Centre, Campo Alto Campo, Elda, 03600 Alicante, Spain; (M.A.M.); (C.H.-F.); (F.A.-A.); (E.O.-C.)
| | - Elena Orgilés-Calpena
- Footwear Technology Centre, Campo Alto Campo, Elda, 03600 Alicante, Spain; (M.A.M.); (C.H.-F.); (F.A.-A.); (E.O.-C.)
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11
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Morozova SM, Korzhikova-Vlakh EG. Fibrillar Hydrogel Based on Cellulose Nanocrystals Crosslinked via Diels-Alder Reaction: Preparation and pH-Sensitive Release of Benzocaine. Polymers (Basel) 2023; 15:4689. [PMID: 38139941 PMCID: PMC10748274 DOI: 10.3390/polym15244689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
A fibrillar hydrogel was obtained by covalent crosslinking via Diels-Alder reaction of two types of cellulose nanocrystals (CNCs) with furan and maleimide groups. Gelation has been studied at various ratios of components and temperatures in the range from 20 to 60 °C. It was shown that the rheological properties of the hydrogel can be optimized by varying the concentration and ratio of components. Due to the rigid structure of the CNCs, the hydrogel could be formed at a concentration of at least 5 wt%; however, it almost does not swell either in water with pH 5 or 7 or in the HBSS buffer. The introduction of aldehyde groups into the CNCs allows for the conjugation of physiologically active molecules containing primary amino groups due to the formation of imine bonds. Here, we used benzocaine as a model drug for conjugation with CNC hydrogel. The resulting drug-conjugated hydrogel demonstrated the stability of formulation at pH 7 and a pH-sensitive release of benzocaine due to the accelerated hydrolytic cleavage of the imine bond at pH < 7. The developed drug-conjugated hydrogel is promising as wound dressings for local anesthesia.
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Affiliation(s)
- Sofia M. Morozova
- Center of Fluid Physics and Soft Matter, N.E. Bauman Moscow State Technical University, 2nd Baumanskaya St. 5/1, 105005 Moscow, Russia
| | - Evgenia G. Korzhikova-Vlakh
- Institute of Macromolecular Compounds of Russian Academy of Sciences, Bolshoy pr. 31, 199004 St. Petersburg, Russia;
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12
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Ionita D, Cristea M, Gaina C, Silion M, Simionescu BC. Evidence through Thermal Analysis of Retro Diels-Alder Reaction in Model Networks Based on Anthracene Modified Polyester Resins. Polymers (Basel) 2023; 15:4028. [PMID: 37836077 PMCID: PMC10575195 DOI: 10.3390/polym15194028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
The present work is focused on polyester resins obtained from the diglycidyl ether of bisphenol A and anthracene modified 5-maleimidoisophthalic acid. Because the maleimide-anthracene Diels-Alder (DA) adduct is stable at high temperatures, it is considered a good option for high performance polymers. However, the information related to the retroDA reaction for this type of adduct is sometimes incoherent. A detailed thermal study (conventional TGA, HiRes TGA, MTGA, DSC, MDSC) was performed in order to establish whether the rDA reaction can be revealed for this type of anthracene modified polyester resins. The TGA method confirmed the cleavage of the anthracene-maleimide DA adduct, while the DSC demonstrated the presence of anthracene in the system. At high temperatures, unprotected maleimide homopolymerizes and/or reacts with allyl groups according to the -ene reaction. Therefore, the thermal DA reaction is not displayed anymore upon the subsequent cooling, and the glass transition region is registered at a higher temperature range during the second heating. The use of sample-controlled thermal analysis (HiRes TGA) and MTGA improved the TGA result; however, it was not possible to separate the very complex degradation processes that are interconnected.
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Affiliation(s)
| | - Mariana Cristea
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica 41A, 700487 Iasi, Romania; (D.I.); (C.G.); (M.S.); (B.C.S.)
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13
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Wang J, Li J, Zhang J, Liu S, Wan L, Liu Z, Huang F. High-Performance Reversible Furan-Maleimide Resins Based on Furfuryl Glycidyl Ether and Bismaleimides. Polymers (Basel) 2023; 15:3470. [PMID: 37631526 PMCID: PMC10459929 DOI: 10.3390/polym15163470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/12/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
Two reversible furan-maleimide resins, in which there are rigid -Ph-CH2-Ph- structures and flexible -(CH2)6- structures in bismaleimides, were synthesized from furfuryl glycidyl ethers (FGE), 4,4'-diaminodiphenyl ether (ODA), N,N'-4,4'-diphenylmethane-bismaleimide (DBMI), and N,N'-hexamethylene-bismaleimide (HBMI). The structures of the resins were confirmed using Fourier transform infrared analysis, and the thermoreversibility was evidenced using differential scanning calorimetry (DSC) analysis, as well as the sol-gel transformation process. Mechanical properties and recyclability of the resins were preliminarily evaluated using the flexural test. The results show the Diels-Alder (DA) reaction occurs at about 90 °C and the reversible DA reaction occurs at 130-140 °C for the furan-maleimide resin. Thermally reversible furan-maleimide resins have high mechanical properties. The flexural strength of cured FGE-ODA-HBMI resin arrives at 141 MPa. The resins have a repair efficiency of over 75%. After being hot-pressed three times, two resins display flexural strength higher than 80 MPa.
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Affiliation(s)
- Jiawen Wang
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
| | - Jixian Li
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
| | - Jun Zhang
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
| | - Shuyue Liu
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
| | - Liqiang Wan
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
| | - Zuozhen Liu
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
- Huachang Polymers Co., Ltd., East China University of Science and Technology, Shanghai 200241, China
| | - Farong Huang
- Key Laboratory for Specially Functional Materials and Related Technology of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China; (J.W.); (S.L.)
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14
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Scheerer JR, Leeth EB, Sprow JA. Synthesis of Guaipyridine Alkaloids Rupestine M and L by Cycloaddition/Cycloreversion of an Intermediate 1,4-Oxazinone. SYNTHESIS-STUTTGART 2023; 55:2319-2324. [PMID: 37691879 PMCID: PMC10489027 DOI: 10.1055/s-0042-1751413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A new method to prepare 1,4-oxazinone intermediates was developed based on aza-conjugate addition of β-amino alcohols to electron-deficient alkyne precursors. A tandem intramolecular cycloaddition/cycloreversion reaction sequence was evaluated, leading to the synthesis of the guaipyridine alkaloid natural products rupestine M and L. Starting from (-)-citronellal and thus a known configuration of the C5 stereocenter, a revised absolute configuration of natural rupestine L is suggested based on optical rotation.
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Affiliation(s)
- Jonathan R Scheerer
- Department of Chemistry, William & Mary, P.O. Box 8795, Williamsburg, VA 23187, USA
| | - Ella B Leeth
- Department of Chemistry, William & Mary, P.O. Box 8795, Williamsburg, VA 23187, USA
| | - Jennifer A Sprow
- Department of Chemistry, William & Mary, P.O. Box 8795, Williamsburg, VA 23187, USA
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15
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Dresler E, Wróblewska A, Jasiński R. Understanding the Molecular Mechanism of Thermal and LA-Catalysed Diels-Alder Reactions between Cyclopentadiene and Isopropyl 3-Nitroprop-2-Enate. Molecules 2023; 28:5289. [PMID: 37513163 PMCID: PMC10386420 DOI: 10.3390/molecules28145289] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/17/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
The molecular mechanism of the Diels-Alder reaction with the participation of cyclopentadiene and isopropyl 3-nitroprop-2-enate was examined based on wb97xd/6-311+G(d) (PCM) quantum chemical calculations. It was found that the type of mechanism for the conversion of addends depends significantly on the reaction conditions. In less-polar environments, a one-step polar mechanism is realised. In more polar solvents, the formation of "extended"-type zwitterionic intermediates is possible. In contrast, in the presence of an LA-type catalyst, the one-step mechanisms are replaced by respective stepwise mechanisms with zwitterionic or heterocyclic intermediates.
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Affiliation(s)
- Ewa Dresler
- Łukasiewicz Research Network-Institute of Heavy Organic Synthesis "Blachownia", Energetyków 9, 47-225 Kędzierzyn-Koźle, Poland
| | - Aneta Wróblewska
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Radomir Jasiński
- Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland
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16
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Aqsha A, Winoto HP, Adhi TP, Adisasmito S, Ramli Y, Siddiq L, Pratama FB, Ramdani MR, Indarto A. Sequential Esterification-Diels-Alder Reactions for Improving Pine Rosin Durability within Road Marking Paint. Molecules 2023; 28:5236. [PMID: 37446897 DOI: 10.3390/molecules28135236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/13/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Pine rosin, which is derived from Pinus merkusii resin, a natural product, has demonstrated potential as a road marking binder. Although pine rosin has an excellent shinning property, it has some limitations, such as instability and color change. To tackle these issues, modified rosin has been developed through sequential esterification and Diels-Alder reactions, and it has shown better properties than untreated rosin. In this study, from the evaluation of untreated and treated rosins, the treated rosin showed some improvements, such as a lower acid value and higher stability, as shown by the color consistency during the oxidation test at 150 °C for 24 h in open-air conditions. Additionally, as road marking paint, the modified rosin is blended with blending materials in the range of 18-28 wt.%. The modified rosin has a softening point of 170-210 °C, a hardness of 50-71 HD, and a weight loss of 1.33-5.12 mg during the wearing test. These results are comparable to or better than those of commercially available road marking products.
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Affiliation(s)
- Aqsha Aqsha
- Department of Chemical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
- Department of Bioenergy Engineering and Chemurgy, Institut Teknologi Bandung, Jalan Let. Jen. Purn. Dr. (HC), Mashudi No. 1, Sumedang 45363, Indonesia
| | - Haryo Pandu Winoto
- Department of Chemical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
| | - Tri Partono Adhi
- Department of Chemical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
| | - Sanggono Adisasmito
- Department of Chemical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
| | - Yusrin Ramli
- Graduate School of Science and Technology, Hirosaki University, 1-Bunkyocho, Hirosaki 036-8560, Japan
| | - Lathifuddin Siddiq
- Department of Bioenergy Engineering and Chemurgy, Institut Teknologi Bandung, Jalan Let. Jen. Purn. Dr. (HC), Mashudi No. 1, Sumedang 45363, Indonesia
| | - Fauzi Bhakti Pratama
- Department of Bioenergy Engineering and Chemurgy, Institut Teknologi Bandung, Jalan Let. Jen. Purn. Dr. (HC), Mashudi No. 1, Sumedang 45363, Indonesia
| | - Mohammad Reza Ramdani
- Department of Bioenergy Engineering and Chemurgy, Institut Teknologi Bandung, Jalan Let. Jen. Purn. Dr. (HC), Mashudi No. 1, Sumedang 45363, Indonesia
| | - Antonius Indarto
- Department of Chemical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
- Department of Bioenergy Engineering and Chemurgy, Institut Teknologi Bandung, Jalan Let. Jen. Purn. Dr. (HC), Mashudi No. 1, Sumedang 45363, Indonesia
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17
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Tong L, Zhou M, Chen Y, Lu K, Zhang Z, Mu Y, He Z. A New Self-Healing Degradable Copolymer Based on Polylactide and Poly(p-dioxanone). Molecules 2023; 28:molecules28104021. [PMID: 37241762 DOI: 10.3390/molecules28104021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
In this paper, the copolymerization of poly (p-dioxanone) (PPDO) and polylactide (PLA) was carried out via a Diels-Alder reaction to obtain a new biodegradable copolymer with self-healing abilities. By altering the molecular weights of PPDO and PLA precursors, a series of copolymers (DA2300, DA3200, DA4700 and DA5500) with various chain segment lengths were created. After verifying the structure and molecular weight by 1H NMR, FT-IR and GPC, the crystallization behavior, self-healing properties and degradation properties of the copolymers were evaluated by DSC, POM, XRD, rheological measurements and enzymatic degradation. The results show that copolymerization based on the DA reaction effectively avoids the phase separation of PPDO and PLA. Among the products, DA4700 showed a better crystallization performance than PLA, and the half-crystallization time was 2.8 min. Compared to PPDO, the heat resistance of the DA copolymers was improved and the Tm increased from 93 °C to 103 °C. Significantly, the rheological data also confirmed that the copolymer was self-healing and showed obvious self-repairing properties after simple tempering. In addition, an enzyme degradation experiment showed that the DA copolymer can be degraded by a certain amount, with the degradation rate lying between those of PPDO and PLA.
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Affiliation(s)
- Laifa Tong
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Mi Zhou
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Yulong Chen
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Kai Lu
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Zhaohua Zhang
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Yuesong Mu
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
| | - Zejian He
- Material Science and Engineering, College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310000, China
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18
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Aitken RA, Power LA, Slawin AMZ. New Chemistry of Chiral 1,3-Dioxolan-4-Ones. Molecules 2023; 28:molecules28093845. [PMID: 37175260 PMCID: PMC10180285 DOI: 10.3390/molecules28093845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
(2S,5S)-5-Phenyl-2-t-butyl-1,3-dioxolan-4-one, readily derived from mandelic acid, undergoes the Michael addition to butenolide and 4-methoxy-β-nitrostyrene with the absolute configuration of the products confirmed by X-ray diffraction in each case. In the former case, thermal fragmentation gives the phenyl ketone, thus illustrating use of the dioxolanone as a chiral benzoyl anion equivalent. The Diels-Alder cycloaddition chemistry of (2S)-5-methylene-2-t-butyl-1,3-dioxolan-4-one, derived from lactic acid, has been further examined with the X-ray structures of four adducts determined. In one case, thermal fragmentation of the adduct gives a chiral epoxy ketone resulting from the dioxolanone acting as a chiral ketene equivalent, while in others the products give insight into the mechanism of the dioxolanone fragmentation process.
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Affiliation(s)
- R Alan Aitken
- EaStCHEM School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Lynn A Power
- EaStCHEM School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Alexandra M Z Slawin
- EaStCHEM School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
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19
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Sorokina SA, Kuchkina NV, Mikhalchenko AV, Krasnova IY, Khanin DA, Skupov KM, Shifrina ZB. Ultramicroporous Polyphenylenes via Diels-Alder Polycondensation Approach. Polymers (Basel) 2023; 15:polym15092060. [PMID: 37177207 PMCID: PMC10181309 DOI: 10.3390/polym15092060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/24/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
Development of new microporous organic polymers attracts significant attention due to a wide scope of promising applications. In addition, the synthesis of soluble, non-crosslinking polymers of high surface area and uniform microporosity is very challenging, and the methods for soluble microporous polymers formation are rather limited. In this work, we report a new approach to construct porous polyphenylenes which employs the Diels-Alder polycondensation of multifunctional ethynyl-containing monomers of different spatial architecture with bis(cyclopentadienone)s. The resulting polymers were soluble in common organic solvents, and their structure and properties were assessed by NMR, TGA, DSC, and SEC studies. The polymers demonstrated a specific surface area up to 751 m2·g-1 and ultramicroporous (pore size ≤ 0.6 nm) structure. N2 and CO2 adsorption-desorption data revealed that porosity parameters, e.g., specific surface area and pore sizes, can be tuned selectively by varying the type of monomers and reaction conditions.
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Affiliation(s)
- Svetlana A Sorokina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Nina V Kuchkina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Alexander V Mikhalchenko
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Irina Yu Krasnova
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Dmitry A Khanin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Kirill M Skupov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
| | - Zinaida B Shifrina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St., 119991 Moscow, Russia
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20
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Shybanov DE, Kukushkin ME, Hrytseniuk YS, Grishin YK, Roznyatovsky VA, Tafeenko VA, Skvortsov DA, Zyk NV, Beloglazkina EK. [4+2]-Cycloaddition to 5-Methylidene-Hydantoins and 5-Methylidene-2-Thiohydantoins in the Synthesis of Spiro-2-Chalcogenimidazolones. Int J Mol Sci 2023; 24. [PMID: 36902468 DOI: 10.3390/ijms24055037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023] Open
Abstract
Novel hydantion and thiohydantoin-based spiro-compounds were prepared via theDiels-Alder reactions between 5-methylidene-hydantoins or 5-methylidene-2-thiohydantoins and 1,3-dienes (cyclopentadiene, cyclohexadiene, 2,3-dimethylbutadiene, isoprene). It was shown that the cycloaddition reactions proceed regioselectively and stereoselectively with the formation of exo-isomers in the reactions with cyclic dienes andthe less sterically hindered products in the reactions with isoprene. Reactions of methylideneimidazolones with cyclopentadiene proceed viaco-heating the reactants; reactions with cyclohexadiene, 2,3-dimethylbutadiene, and isoprene require catalysis by Lewis acids. It was demonstrated that ZnI2 is an effective catalyst in the Diels-Alder reactions of methylidenethiohydantoins with non-activated dienes. The possibility of alkylation and acylation of the obtained spiro-hydantoinsat the N(1)nitrogen atoms with PhCH2Cl or Boc2O and the alkylation of the spiro-thiohydantoinsat the S atoms with MeI or PhCH2Cl in high yields have been demonstrated. The preparativetransformation of spiro-thiohydantoins into corresponding spiro-hydantoinsin mild conditions by treating with 35% aqueous H2O2 or nitrile oxide has been carried out. The obtained compounds show moderate cytotoxicity in the MTT test on MCF7, A549, HEK293T, and VA13 cell lines. Some of the tested compounds demonstrated some antibacterial effect against Escherichia coli (E. coli) BW25113 DTC-pDualrep2 but were almost inactive against E. coli BW25113 LPTD-pDualrep2.
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21
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McReynolds BT, Mojtabai KD, Penners N, Kim G, Lindholm S, Lee Y, McCoy JD, Chowdhury S. Understanding the Effect of Side Reactions on the Recyclability of Furan-Maleimide Resins Based on Thermoreversible Diels-Alder Network. Polymers (Basel) 2023; 15. [PMID: 36904347 DOI: 10.3390/polym15051106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
We studied the effect of side reactions on the reversibility of epoxy with thermoreversible Diels-Alder (DA) cycloadducts based on furan and maleimide chemistry. The most common side reaction is the maleimide homopolymerization which introduces irreversible crosslinking in the network adversely affecting the recyclability. The main challenge is that the temperatures at which maleimide homopolymerization can occur are approximately the same as the temperatures at which retro-DA (rDA) reactions depolymerize the networks. Here we conducted detailed studies on three different strategies to minimize the effect of the side reaction. First, we controlled the ratio of maleimide to furan to reduce the concentration of maleimide groups which diminishes the effects of the side reaction. Second, we applied a radical-reaction inhibitor. Inclusion of hydroquinone, a known free radical scavenger, is found to retard the onset of the side reaction both in the temperature sweep and isothermal measurements. Finally, we employed a new trismaleimide precursor that has a lower maleimide concentration and reduces the rate of the side reaction. Our results provide insights into how to minimize formation of irreversible crosslinking by side reactions in reversible DA materials using maleimides, which is important for their application as novel self-healing, recyclable, and 3D-printable materials.
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22
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Torres P, Guillén M, Escribà M, Crusats J, Moyano A. Synthesis of New Amino-Functionalized Porphyrins:Preliminary Study of Their Organophotocatalytic Activity. Molecules 2023; 28. [PMID: 36838985 DOI: 10.3390/molecules28041997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 02/25/2023] Open
Abstract
The design, synthesis, and initial study of amino-functionalized porphyrins as a new class of bifunctional catalysts for asymmetric organophotocatalysis is described. Two new types of amine-porphyrin hybrids derived from 5,10,15,20-tetraphenylporphyrin (TPPH2), in which a cyclic secondary amine moiety is covalently linked either to a β-pyrrolic position (Type A) or to the p-position of one of the meso phenyl groups (Type B), were prepared by condensation, reductive amination, or amidation reactions from the suitable porphyrins (either formyl or methanamine derivatives) with readily available chiral amines. A preliminary study of the possible use of Type A amine-porphyrin hybrids as asymmetric, bifunctional organophotocatalysts was performed using the chiral, imidazolidinone-catalyzed Diels-Alder cycloaddition between cyclopentadiene 28 and trans-cinnamaldehyde 29 as a benchmark reaction. The yield and the stereochemical outcome of this process, obtained under purely organocatalytic conditions, under dual organophocatalysis, and under bifunctional organophotocatalysis, were compared.
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23
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Bednarczyk P, Mozelewska K, Klebeko J, Rokicka J, Ossowicz-Rupniewska P. Impact of the Chemical Structure of Photoreactive Urethane (Meth)Acrylates with Various (Meth)Acrylate Groups and Built-In Diels-Alder Reaction Adducts on the UV-Curing Process and Self-Healing Properties. Polymers (Basel) 2023; 15:polym15040924. [PMID: 36850208 PMCID: PMC9967232 DOI: 10.3390/polym15040924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/05/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023] Open
Abstract
A series of UV-curable urethane (meth)acrylates were obtained by copolymerization of the Diels-Alder adduct (HODA), isophorone diisocyanate, PEG1000, and various hydroxy (meth)acrylates. The aim of the present work was to determine the influence of the chemical structure of the introduced (meth)acrylic groups, i.e., hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate, on the UV-curing process and self-healing properties of cured coatings. The chemical structure of prepolymers was characterized by FTIR and NMR spectroscopy, whereas the UV-curing process was monitored in real time using FTIR and photo-DSC. In turn, the self-healing properties were characterized in relation to the thermally reversible mechanism, which was tested using the following methods: an FTIR spectroscope equipped with a heating attachment; DSC and TG apparatus; and an optical microscope equipped with a stage with programmable heating. The result of comprehensive research on the self-healing of photocurable coatings in the context of the presence of various photoreactive groups and the course of the curing process allows one to control the self-healing process by reducing the effective healing temperature. The self-healing properties, taken together with the fast UV curing of the coatings and excellent properties of cured coatings, make the material attractive for a variety of applications, in particular in cases where coatings are not repaired, e.g., for economic reasons or when it is not possible, such as in flexible electronic screens, car paint film, and aircraft interior finishes.
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24
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Morozova SM. Recent Advances in Hydrogels via Diels-Alder Crosslinking: Design and Applications. Gels 2023; 9:gels9020102. [PMID: 36826272 PMCID: PMC9956184 DOI: 10.3390/gels9020102] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 01/27/2023] Open
Abstract
The Diels-Alder (DA) reaction is a promising tool for obtaining covalently crosslinked hydrogels due to its reaction bioorthogonality, the absence of by-products, and the application of mild conditions without a catalyst. The resulting hydrogels are in demand for use in various fields of materials science and biomedicine. While the dynamic nature of the cycloaddition of diene and dienophile has previously been used extensively for the fabrication of self-healing materials, it has only recently spread to the expansion of the functional properties of polymer gels for bioapplications. This review describes strategies and recent examples of obtaining hydrogels based on the DA reaction, demonstrating that the emerging functional properties go beyond self-healing. The types of classifications of hydrogels are listed, depending on the type of reaction and the nature of the components. Examples of obtaining hydrogels based on the normal and inverse electron-demand DA reaction, as well as the application of hydrogels for cell culture, drug delivery, injectable gels, and wound dressings, are considered. In conclusion, possible developmental directions are discussed, including the use of diene-dienophile pairs with a low temperature for the reversal of DA reaction, the modification of nanoparticles by diene and/or dienophile fragments, and new applications such as ink for 3D printing, sensing hydrogels, etc.
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Affiliation(s)
- Sofia M Morozova
- Center NTI "Digital Materials Science: New Materials and Substances", N.E. Bauman Moscow State Technical University, 2nd Baumanskaya St. 5/1, Moscow 105005, Russia
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25
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Štrbac P, Briš A, Margetić D. N,N'-Di-Boc-2H-Isoindole-2-carboxamidine-First Guanidine-Substituted Isoindole. Molecules 2022; 27. [PMID: 36558087 DOI: 10.3390/molecules27248954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/10/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Abstract
Synthesis of N,N'-Di-Boc-2H-isoindole-2-carboxamidine, the first representative of isoindoles containing guanidine functionality, was carried out. The cycloaddition reactivity of this new Diels-Alder heterodiene was studied and the title compound was employed as a cycloaddition delivery reagent for guanidine functionality. Higher reactivity was found in comparison with the corresponding pyrrole derivative. Substitution with fluorine or guanidine functionality does not change the reactivities of isoindoles, and these findings are in good accord with computational results.
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Platonova E, Ponomareva P, Lokiaeva Z, Pavlov A, Nelyub V, Polezhaev A. New Building Blocks for Self-Healing Polymers. Polymers (Basel) 2022; 14. [PMID: 36559760 DOI: 10.3390/polym14245394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/01/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
The healing efficiency in self-healing materials is bound by the ability to form blends between the prepolymer and curing agent. One of the problems in the development of self-healing polymers is the reduced affinity of the bismaleimide curing agent for the elastomeric furan-containing matrix. Even when stoichiometric amounts of both components are applied, incompatibility of components can significantly reduce the effectiveness of self-healing, and lead to undesirable side effects, such as crystallization of the curing agent, in the thickness and on the surface. This is exactly what we have seen in the development of linear and cross-linked PUs using BMI as a hardener. In this work, we present a new series of the di- and tetrafuranic isocyanate-related ureas-promising curing agents for the development of polyurethanes-like self-healing materials via the Diels-Alder reaction. The commonly used isocyanates (4,4'-Methylene diphenyl diisocyanate, MDI; 2,4-Tolylene diisocyanate, TDI; and Hexamethylene diisocyanate, HDI) and furfurylamine, difurfurylamine, and furfuryl alcohol (derived from biorenewables) as furanic compounds were utilized for synthesis. The remendable polyurethane for testing was synthesized from a maleimide-terminated prepolymer and one of the T-series urea. Self-healing properties were investigated by thermal analysis. Molecular mass was determined by gel permeation chromatography. The properties of the new polymer were compared with polyurethane from a furan-terminated analog. Visual tests showed that the obtained material has thermally induced self-healing abilities. Resulting polyurethane (PU) has a rather low fusing point and thus may be used as potential material for Fused Deposition Modeling (FDM) 3D printing.
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Pöschl M, Gopi Sathi S, Stoček R. Tuning the Curing Efficiency of Conventional Accelerated Sulfur System for Tailoring the Properties of Natural Rubber/Bromobutyl Rubber Blends. Materials (Basel) 2022; 15:8466. [PMID: 36499962 PMCID: PMC9740831 DOI: 10.3390/ma15238466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
The state of cure and the vulcanizate properties of a conventional accelerated sulfur (CV) cured 50/50 blend of natural rubber (NR) and bromobutyl rubber (BIIR) were inferior. However, this blend exhibits a higher extent of cure with remarkable improvements in its mechanical properties, particularly the tensile strength, modulus and hardness after curing with a combination of accelerated sulfur and three parts per hundred rubber (phr) of a bismaleimide (MF3). Moreover, with the use of 0.25 phr of dicumyl peroxide (DCP) along with the CV/MF3 system, the compression set property of the CV-only cured blend could be reduced from 68% to 15%. The enhanced compatibility between NR and BIIR with the aid of bismaleimide via the Diels-Alder reaction was identified as the primary reason for the improved cure state and the mechanical properties. However, the incorporation of a certain amount of bismaleimide as a crosslink in the NR phase of the blend, via a radical initiated crosslinking process by the action of DCP, is responsible for the improved compression set properties.
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Isamura BK, Lobb KA. A multiscale ONIOM study of the buckminsterfullerene (C 60) Diels-Alder reaction: from model design to reaction path analysis. J Mol Model 2022; 28:327. [PMID: 36138156 DOI: 10.1007/s00894-022-05319-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/06/2022] [Indexed: 11/29/2022]
Abstract
The hybrid ONIOM (Our own N-layered Integrated molecular Orbital and molecular Mechanics) formalism is employed to investigate the Diels-Alder reaction of the buckminsterfullerene C60. Our computations suggest that the ONIOM2(M06-2X/6-31G(d): SVWN/STO-3G) model, enclosing both the diene and the pyracyclene fragment of C60 in the higher-layer, provides a reasonable trade-off between accuracy and computational cost as it comes to predicting reaction energetics. Moreover, the frontier molecular orbital (FMO) theory and activation strain model (ASM) are jointly relied on to rationalize the effect of -OH and -CN substituents on the activation barrier of this reaction. Finally, reaction paths are scrutinized to get insight into the various forces underpinning the process of cycloadduct formation.
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Affiliation(s)
| | - Kevin Alan Lobb
- Department of Chemistry, Rhodes University, Eastern Cape, Makhanda, 6140, South Africa.,Research Unit in Bioinformatics (RUBi), Rhodes University, Eastern Cape, Makhanda, 6140, South Africa
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Isamura BK, Lobb KA. AMADAR: a python-based package for large scale prediction of Diels-Alder transition state geometries and IRC path analysis. J Cheminform 2022; 14:39. [PMID: 35706060 PMCID: PMC9202188 DOI: 10.1186/s13321-022-00618-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 05/25/2022] [Indexed: 12/28/2022] Open
Abstract
Predicting transition state geometries is one of the most challenging tasks in computational chemistry, which often requires expert-based knowledge and permanent human intervention. This short communication reports technical details and preliminary results of a python-based tool (AMADAR) designed to generate any Diels–Alder (DA) transition state geometry (TS) and analyze determined IRC paths in a (quasi-)automated fashion, given the product SMILES. Two modules of the package are devoted to performing, from IRC paths, reaction force analyses (RFA) and atomic (fragment) decompositions of the reaction force F and reaction force constant \documentclass[12pt]{minimal}
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\begin{document}$$\kappa$$\end{document}κ. The performance of the protocol has been assessed using a dataset of 2000 DA cycloadducts retrieved from the ZINC database. The sequential location of the corresponding TSs was achieved with a success rate of 95%. RFA plots confirmed the reaction force constant \documentclass[12pt]{minimal}
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\begin{document}$$\kappa$$\end{document}κ to be a good indicator of the (non)synchronicity of the associated DA reactions. Moreover, the atomic decomposition of \documentclass[12pt]{minimal}
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\begin{document}$$\kappa$$\end{document}κ allows for the rationalization of the (a)synchronicity of each DA reaction in terms of contributions stemming from pairs of interacting atoms. The source code of the AMADAR tool is available on GitHub [CMCDD/AMADAR(github.com)] and can be used directly with minor customizations, mostly regarding the local working environment of the user.
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Affiliation(s)
- Bienfait K Isamura
- Department of Chemistry, Rhodes University, Makhanda, 6140, South Africa
| | - Kevin A Lobb
- Department of Chemistry, Rhodes University, Makhanda, 6140, South Africa. .,Research Unit in BioInformatics (RUBi), Rhodes University, Makhanda, 6140, South Africa.
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Watanabe K, Sato M, Osada H. Recent advances in the chemo-biological characterization of decalin natural products and unraveling of the workings of Diels-Alderases. Fungal Biol Biotechnol 2022; 9:9. [PMID: 35488322 PMCID: PMC9055775 DOI: 10.1186/s40694-022-00139-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/15/2022] [Indexed: 11/19/2022] Open
Abstract
The Diels–Alder (DA) reaction refers to a [4 + 2] cycloaddition reaction that falls under the category of pericyclic reactions. It is a reaction that allows regio- and stereo-selective construction of two carbon–carbon bonds simultaneously in a concerted manner to generate a six-membered ring structure through a six-electron cyclic transition state. The DA reaction is one of the most widely applied reactions in organic synthesis, yet its role in biological systems has been debated intensely over the last four decades. A survey of secondary metabolites produced by microorganisms suggests strongly that many of the compounds possess features that are likely formed through DA reactions, and most of them are considered to be catalyzed by enzymes that are commonly referred to as Diels–Alderases (DAases). In recent years, especially over the past 10 years or so, we have seen an accumulation of a substantial body of work that substantiates the argument that DAases indeed exist and play a critical role in the biosynthesis of complex metabolites. This review will cover the DAases involved in the biosynthesis of decalin moieties, which are found in many of the medicinally important natural products, especially those produced by fungi. In particular, we will focus on a subset of secondary metabolites referred to as pyrrolidine-2-one-bearing decalin compounds and discuss the decalin ring stereochemistry and the biological activities of those compounds. We will also look into the genes and enzymes that drive the biosynthetic construction of those complex natural products, and highlight the recent progress made on the structural and mechanistic understanding of DAases, especially regarding how those enzymes exert stereochemical control over the [4 + 2] cycloaddition reactions they catalyze.
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Affiliation(s)
- Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
| | - Michio Sato
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan
| | - Hiroyuki Osada
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan. .,Chemical Resource Development Research Unit, RIKEN Center for Sustainable Resource Science, Wako-shi, 351-0198, Japan.
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Ruiz-Pardo C, Silva-Gutiérrez L, Lizardi-Mendoza J, López-Franco Y, Peniche-Covas C, Argüelles-Monal W. Chitosan Hydrogels Based on the Diels-Alder Click Reaction: Rheological and Kinetic Study. Polymers (Basel) 2022; 14:1202. [PMID: 35335533 DOI: 10.3390/polym14061202] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 02/04/2023] Open
Abstract
The Diels–Alder reaction is recognized to generate highly selective and regiospecific cycloadducts. In this study, we carried out a rheological and kinetic study of N-furfuryl chitosan hydrogels based on the Diels–Alder click reaction with different poly(ethylene)glycol-maleimide derivatives in dilute aqueous acidic solutions. It was possible to prepare clear and transparent hydrogels with excellent mechanical properties. Applying the Winter and Chambon criterion the gel times were estimated at different temperatures, and the activation energy was calculated. The higher the temperature of gelation, the higher the reaction rate. The crosslinking density and the elastic properties seem to be controlled by the diffusion of the polymer segments, rather than by the kinetics of the reaction. An increase in the concentration of any of the two functional groups is accompanied by a higher crosslinking density regardless maleimide:furan molar ratio. The hydrogel showed an improvement in their mechanical properties as the temperature increases up to 70 °C. Above that, there is a drop in G’ values indicating that there is a process opposing to the Diels–Alder reaction, most likely the retro-Diels–Alder.
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Soares MIL, Cardoso AL, Pinho E Melo TMVD. Diels-Alder Cycloaddition Reactions in Sustainable Media. Molecules 2022; 27:1304. [PMID: 35209094 DOI: 10.3390/molecules27041304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 11/17/2022]
Abstract
Diels–Alder cycloaddition reaction is one of the most powerful strategies for the construction of six-membered carbocyclic and heterocyclic systems, in most cases with high regio- and stereoselectivity. In this review, an insight into the most relevant advances on sustainable Diels–Alder reactions since 2010 is provided. Various environmentally benign solvent systems are discussed, namely bio-based derived solvents (such as glycerol and gluconic acid), polyethylene glycol, deep eutectic solvents, supercritical carbon dioxide, water and water-based aqueous systems. Issues such as method’s scope, efficiency, selectivity and reaction mechanism, as well as sustainability, advantages and limitations of these reaction media, are addressed.
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Yadav S, Ramesh K, Kumar P, Jo SH, Yoo SII, Gal YS, Park SH, Lim KT. Near-Infrared Light-Responsive Shell-Crosslinked Micelles of Poly(d,l-lactide)- b-poly((furfuryl methacrylate)- co-( N-acryloylmorpholine)) Prepared by Diels-Alder Reaction for the Triggered Release of Doxorubicin. Materials (Basel) 2021; 14:7913. [PMID: 34947507 PMCID: PMC8705764 DOI: 10.3390/ma14247913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 01/05/2023]
Abstract
In the present study, we developed near-infrared (NIR)-responsive shell-crosslinked (SCL) micelles using the Diels-Alder (DA) click reaction between an amphiphilic copolymer poly(d,l-lactide)20-b-poly((furfuryl methacrylate)10-co-(N-acryloylmorpholine)78) (PLA20-b-P(FMA10-co-NAM78)) and a diselenide-containing crosslinker, bis(maleimidoethyl) 3,3'-diselanediyldipropionoate (BMEDSeDP). The PLA20-b-P(FMA10-co-NAM78) copolymer was synthesized by RAFT polymerization of FMA and NAM using a PLA20-macro-chain transfer agent (PLA20-CTA). The DA reaction between BMEDSeDP and the furfuryl moieties in the copolymeric micelles in water resulted in the formation of SCL micelles. The SCL micelles were analyzed by 1H-NMR, FE-SEM, and DLS. An anticancer drug, doxorubicin (DOX), and an NIR sensitizer, indocyanine green (ICG), were effectively incorporated into the SCL micelles during the crosslinking reaction. The DOX/ICG-loaded SCL micelles showed pH- and NIR-responsive drug release, where burst release was observed under NIR laser irradiation. The in vitro cytotoxicity analysis demonstrated that the SCL was not cytotoxic against normal HFF-1 cells, while DOX/ICG-loaded SCL micelles exhibited significant antitumor activity toward HeLa cells. Thus, the SCL micelles of PLA20-b-P(FMA10-co-NAM78) can be used as a potential delivery vehicle for the controlled drug release in cancer therapy.
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Affiliation(s)
- Sonyabapu Yadav
- Department of Display Engineering, Pukyong National University, Busan 48513, Korea; (S.Y.); (K.R.); (P.K.)
| | - Kalyan Ramesh
- Department of Display Engineering, Pukyong National University, Busan 48513, Korea; (S.Y.); (K.R.); (P.K.)
- Department of Chemistry, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Parveen Kumar
- Department of Display Engineering, Pukyong National University, Busan 48513, Korea; (S.Y.); (K.R.); (P.K.)
| | - Sung-Han Jo
- Department of Biomedical Engineering, Pukyong National University, Busan 48513, Korea; (S.-H.J.); (S.-H.P.)
| | - Seong II Yoo
- Department of Polymer Engineering, Pukyong National University, Busan 48513, Korea;
| | - Yeong-Soon Gal
- Department of Fire Safety, Kyungil University, Gyeongsan 38428, Korea;
| | - Sang-Hyug Park
- Department of Biomedical Engineering, Pukyong National University, Busan 48513, Korea; (S.-H.J.); (S.-H.P.)
| | - Kwon Taek Lim
- Department of Display Engineering, Pukyong National University, Busan 48513, Korea; (S.Y.); (K.R.); (P.K.)
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Wojaczyńska E, Steppeler F, Iwan D, Scherrmann MC, Marra A. Synthesis and Applications of Carbohydrate-Based Organocatalysts. Molecules 2021; 26:7291. [PMID: 34885873 PMCID: PMC8659088 DOI: 10.3390/molecules26237291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/22/2022] Open
Abstract
Organocatalysis is a very useful tool for the asymmetric synthesis of biologically or pharmacologically active compounds because it avoids the use of noxious metals, which are difficult to eliminate from the target products. Moreover, in many cases, the organocatalysed reactions can be performed in benign solvents and do not require anhydrous conditions. It is well-known that most of the above-mentioned reactions are promoted by a simple aminoacid, l-proline, or, to a lesser extent, by the more complex cinchona alkaloids. However, during the past three decades, other enantiopure natural compounds, the carbohydrates, have been employed as organocatalysts. In the present exhaustive review, the detailed preparation of all the sugar-based organocatalysts as well as their catalytic properties are described.
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Affiliation(s)
- Elżbieta Wojaczyńska
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Franz Steppeler
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Dominika Iwan
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Marie-Christine Scherrmann
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, Bâtiment 420, 91405 Orsay, France
| | - Alberto Marra
- Institut des Biomolécules Max Mousseron (IBMM-UMR 5247), Université de Montpellier, Pôle Chimie Balard Recherche, 1919 Route de Mende, 34293 Montpellier, France
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Zhang J, Ouyang Q, Gui Q, Chen X. Ultrasonic-Assisted Diels-Alder Reaction Exfoliation of Graphite into Graphene with High Resveratrol Adsorption Capacity. Nanomaterials (Basel) 2021; 11:nano11113060. [PMID: 34835824 PMCID: PMC8623989 DOI: 10.3390/nano11113060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 11/24/2022]
Abstract
Scalable preparation of graphene with high adsorption capacity is an important prerequisite for fully realizing its commercial application. Herein, we propose an environmentally friendly route for exfoliation of graphene, which is established based on the Diels–Alder reaction. In our route, N-(4-hydroxyl phenyl) maleimide enters between the flakes as an intercalating agent and participates in the Diels–Alder reaction as a dienophile to increase the interlayer spacing of graphite. Then, graphite is exfoliated into graphene with the aid of ultrasound. The exfoliated product is hydroxyl phenyl functionalized graphene with a thickness of 0.5–1.5 nm and an average lateral size of about 500–800 nm. The exfoliation process does not involve any acid or catalyst and would be a safe and environmentally friendly approach. In addition, the exfoliated graphite shows high resveratrol adsorption capacity, which is ten times that of macroporous resins reported in the literature. Thus, the method proposed herein yields exfoliated graphite with high resveratrol adsorption capacity and is of great significance for the mass production of graphene for practical applications.
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36
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Farshchi N, Gedan-Smolka M, Stommel M. Preparation and Characterization of Self-Healing Polyurethane Powder Coating Using Diels-Alder Reaction. Polymers (Basel) 2021; 13:3803. [PMID: 34771360 DOI: 10.3390/polym13213803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/17/2022] Open
Abstract
Although powder coating systems offer many environmental, ecological and energy related benefits over liquid based coatings, in the case of uretdione based polyurethane systems, high curing temperature is still an issue. On the other hand, powder coating systems make it possible to reduce the costs and enhance the process of forming complex 3D structures using the deep drawing method by pre-coated metal substrates. During this processing method, there is a probability of micro crack formation in the coated film due to strain impact on the coating layer. A powder coating with self-healing ability is an ultimate solution to face not only this kind of fraction but also any other possible ones (such as defects caused by any impact on film surface during processing, transporting or even service). Here, a single molecule that is prepared via Diels–Alder cycloaddition reaction and retro Diels–Alder cleavage reaction was utilized as a self-healing additive to achieve self-healing ability in the powder coating system that is based on a commercially available uretdione cross-linker and OH-polyester resin. Coatings were prepared through melt mixing of components in a lab mixer, milling, sieving, and then application on the metal substrate through the electrostatic spraying method. To illustrate the role of self-healing additive, various concentrations (4 and 9% wt.) in combination with different curing temperatures (80 °C to 200 °C) were investigated. Both samples containing HA showed self-healing ability at elevated temperature around 120 °C for about 30 min with acceptable roughness and surface properties. Hardness measurement of cured film as well as thermal investigation indicate the chemical reaction of HA in a cross-linked network of cross-linker and resin. In addition, using HA leads to a 40 K drop in curing temperature of the system without using any catalyst. A 2.58% improvement in hardness values at a lower curing temperature and healing time of around 12.5 min at 120 °C to recover 100% of initial scratch (more than 10 cycles) in the sample containing 9% wt. HA was observed.
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Atioğlu Z, Akkurt M, Mammadova GZ, Mlowe S. Crystal structure and Hirshfeld surface analysis of (3a SR,6 RS,6a SR,7 RS,11b SR,11c RS)-2,2-dibenzyl-2,3,6a,11c-tetra-hydro-1 H,6 H,7 H-3a,6:7,11b-di-epoxy-dibenzo[ de, h]isoquinolin-2-ium tri-fluoro-methane-sulfonate. Acta Crystallogr E Crystallogr Commun 2021; 77:1072-1077. [PMID: 34868638 PMCID: PMC8587987 DOI: 10.1107/s2056989021010173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
In the cation of the title salt, C30H28NO2 +·CF3O3S-, the four tetra-hydro-furan rings adopt envelope conformations. In the crystal, pairs of cations are linked by dimeric C-H⋯O hydrogen bonds, forming two R 2 2(6) ring motifs parallel to the (001) plane. The cations and anions are connected by further C-H⋯O hydrogen bonds, forming a three-dimensional network structure. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (47.6%), C⋯H/H⋯C (20.6%), O⋯H/H⋯O (18.0%) and F⋯H/H⋯F (9.9%) inter-actions.
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Affiliation(s)
- Zeliha Atioğlu
- Department of Aircraft Electrics and Electronics, School of Applied Sciences, Cappadocia University, Mustafapaşa, 50420 Ürgüp, Nevşehir, Turkey
| | - Mehmet Akkurt
- Department of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Turkey
| | - Gunay Z. Mammadova
- Department of Chemistry, Baku State University, Z. Khalilov str. 23, AZ, 1148 Baku, Azerbaijan
| | - Sixberth Mlowe
- University of Dar es Salaam, Dar es Salaam University College of Education, Department of Chemistry, PO Box 2329, Dar es Salaam, Tanzania
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Fang RJ, Yan C, Sun J, Han Y, Yan CG. Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4 -c]carbazoles via domino Diels-Alder reaction. Beilstein J Org Chem 2021; 17:2425-2432. [PMID: 34621404 PMCID: PMC8450976 DOI: 10.3762/bjoc.17.159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/06/2021] [Indexed: 12/15/2022] Open
Abstract
The p-TsOH-catalyzed Diels–Alder reaction of 3-(indol-3-yl)maleimides with chalcone in toluene at 60 °C afforded two diastereoisomers of tetrahydropyrrolo[3,4-c]carbazoles, which can be dehydrogenated by DDQ oxidation in acetonitrile at room temperature to give the aromatized pyrrolo[3,4-c]carbazoles in high yields. On the other hand, the one-pot reaction of 3-(indol-3-yl)-1,3-diphenylpropan-1-ones with chalcones or benzylideneacetone in acetonitrile in the presence of p-TsOH and DDQ resulted in polyfunctionalized carbazoles in satisfactory yields. The reaction mechanism included the DDQ oxidative dehydrogenation of 3-(indol-3-yl)-1,3-diphenylpropan-1-ones to the corresponding 3-vinylindoles, their acid-catalyzed Diels–Alder reaction and sequential aromatization process.
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Affiliation(s)
- Ren-Jie Fang
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Chen Yan
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Jing Sun
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Ying Han
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Chao-Guo Yan
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
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39
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Atioğlu Z, Akkurt M, Mammadova GZ, Bhattarai A. Crystal structure and Hirshfeld surface analysis of 2,2,2-tri-chloro- N, N-bis-{[(1 RS,4 SR)-1,4-di-hydro-1,4-ep-oxy-naphthalen-1-yl]meth-yl}acetamide. Acta Crystallogr E Crystallogr Commun 2021; 77:1048-1053. [PMID: 34667636 PMCID: PMC8491519 DOI: 10.1107/s2056989021009907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022]
Abstract
In the title compound, C24H18Cl3NO3, the tetra-hydro-furan rings adopt envelope conformations. In the crystal, C-H⋯O hydrogen bonds connect mol-ecules, generating layers parallel to the (001) plane. These layers are connected along the c-axis direction by C-H⋯π inter-actions. The packing is further stabilized by inter-layer van der Waals and inter-halogen inter-actions. The most important contributions to the surface contacts are from H⋯H (36.8%), Cl⋯H/H⋯Cl (26.6%), C⋯H/H⋯C (18.8%) and O⋯H/H⋯O (11.3%) inter-actions, as concluded from a Hirshfeld surface analysis.
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Affiliation(s)
- Zeliha Atioğlu
- Department of Aircraft Electrics and Electronics, School of Applied Sciences, Cappadocia University, Mustafapaşa, 50420 Ürgüp, Nevşehir, Turkey
| | - Mehmet Akkurt
- Department of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Turkey
| | - Gunay Z. Mammadova
- Organic Chemistry Department, Baku State University, Z. Khalilov str. 23, AZ 1148 Baku, Azerbaijan
| | - Ajaya Bhattarai
- Department of Chemistry, M.M.A.M.C (Tribhuvan University) Biratnagar, Nepal
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40
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Wang T, Kong WW, Yu WC, Gao JF, Dai K, Yan DX, Li ZM. A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High-Efficient Electromagnetic Interference Shielding. Nanomicro Lett 2021; 13:162. [PMID: 34338928 PMCID: PMC8329141 DOI: 10.1007/s40820-021-00693-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/11/2021] [Indexed: 05/02/2023]
Abstract
The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels-Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.
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Affiliation(s)
- Ting Wang
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Wei-Wei Kong
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Wan-Cheng Yu
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China
| | - Jie-Feng Gao
- The College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225009, People's Republic of China
| | - Kun Dai
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Ding-Xiang Yan
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.
- School of Aeronautics and Astronautics, Sichuan University, Chengdu, 610065, People's Republic of China.
| | - Zhong-Ming Li
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.
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Platonova E, Chechenov I, Pavlov A, Solodilov V, Afanasyev E, Shapagin A, Polezhaev A. Thermally Remendable Polyurethane Network Cross-Linked via Reversible Diels-Alder Reaction. Polymers (Basel) 2021; 13:1935. [PMID: 34200958 PMCID: PMC8230680 DOI: 10.3390/polym13121935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/02/2021] [Accepted: 06/06/2021] [Indexed: 11/21/2022] Open
Abstract
We prepared a series of thermally remendable and recyclable polyurethanes crosslinked via reversible furan-maleimide Diels-Alder reaction based on TDI end-caped branched Voranol 3138 terminated with difurfurylamine and 4,4'-bis(maleimido)diphenylmethane (BMI). We showed that Young modulus strongly depends on BMI content (from 8 to 250 MPa) that allows us to obtain materials of different elasticity as simple as varying BMI content. The ability of DA and retro-DA reactions between furan and maleimide to reversibly bind material components was investigated by NMR spectroscopy, differential scanning calorimetry, and recycle testing. All polymers obtained demonstrated high strengths and could be recovering without significant loss in mechanical properties for at least five reprocessing cycles.
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Affiliation(s)
- Elena Platonova
- Laboratory of Functional Composite Materials, Bauman Moscow State Technical University, 2nd Baumanskaya str., 5/1, 105005 Moscow, Russia; (E.P.); (I.C.); (V.S.)
| | - Islam Chechenov
- Laboratory of Functional Composite Materials, Bauman Moscow State Technical University, 2nd Baumanskaya str., 5/1, 105005 Moscow, Russia; (E.P.); (I.C.); (V.S.)
| | - Alexander Pavlov
- Laboratory for Nuclear Magnetic Resonance, A.N. Nesmeyanov Institute of Organoelement Compounds, Vavilova str., 28, 119334 Moscow, Russia;
| | - Vitaliy Solodilov
- Laboratory of Functional Composite Materials, Bauman Moscow State Technical University, 2nd Baumanskaya str., 5/1, 105005 Moscow, Russia; (E.P.); (I.C.); (V.S.)
- Laboratory of Reinforced Plastics, Semenov Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Egor Afanasyev
- Laboratory for Polymer Materials, A.N. Nesmeyanov Institute of Organoelement Compounds, Vavilova str., 28, 119334 Moscow, Russia;
| | - Alexey Shapagin
- Laboratory of Structural and Morphological Investigations, Frumkin Institute of Physical Chemistry and Electrochemistry, Leninsky Prospect 31, bld.4, 119071 Moscow, Russia;
| | - Alexander Polezhaev
- Laboratory of Functional Composite Materials, Bauman Moscow State Technical University, 2nd Baumanskaya str., 5/1, 105005 Moscow, Russia; (E.P.); (I.C.); (V.S.)
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Abstract
It has been proposed that biosyntheses of many natural products involve pericyclic reactions, including Diels-Alder (DA) reaction. However, only a small set of enzymes have been proposed to catalyze pericyclic reactions. Most surprisingly, there has been no formal identification of natural enzymes that can be defined to catalyze DA reactions (DAases), despite the wide application of the reaction in chemical syntheses of complex organic compounds. However, recent studies began to accumulate a growing body of evidence that supports the notion that enzymes that formally catalyze DA reactions, in fact exist. In this review, I will begin by describing a short history behind the discovery and characterization of macrophomate synthase, one of the earliest enzymes that was proposed to catalyze an intermolecular DA reaction during the biosynthesis of a substituted benzoic acid in a phytopathogenic fungus Macrophoma commelinae. Then, I will discuss representative enzymes that have been chemically authenticated to catalyze DA reactions, with emphasis on more recent discoveries of DAases involved mainly in fungal secondary metabolite biosynthesis except for one example from a marine streptomycete. The current success in identification of a series of DAases and enzymes that catalyze other pericyclic reactions owes to the combined efforts from both the experimental and theoretical approaches in discovering natural products. Such efforts typically involve identifying the chemical features derived from cycloaddition reactions, isolating the biosynthetic genes that encode enzymes that generate such chemical features and deciphering the reaction mechanisms for the enzyme-catalyzed pericyclic reactions.
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Affiliation(s)
- Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan.
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Bauer JB, Diab F, Maichle-Mössmer C, Schubert H, Bettinger HF. Synthesis of the [11]Cyclacene Framework by Repetitive Diels-Alder Cycloadditions. Molecules 2021; 26:3047. [PMID: 34065279 DOI: 10.3390/molecules26103047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 11/16/2022] Open
Abstract
The Diels–Alder cycloaddition between bisdienes and bisdienophile incorporating the 7-oxa-bicyclo[2.2.1]heptane unit are well known to show high diastereoselectivity that can be exploited for the synthesis of molecular belts. The related bisdiene 5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octene is a valuable building block for the synthesis of photoprecursors for acenes, but it has not been employed for the synthesis of molecular belts. The present work investigates by computational means the Diels–Alder reaction between these bisdiene building blocks with syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene, which shows that the diastereoselectivity of the Diels–Alder reaction of the etheno-bridged bisdiene is lower than that of the epoxy-bridged bisdiene. The reaction of the etheno-bridged bisdiene and syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene in 2:1 ratio yields two diastereomers that differ in the orientation of the oxa and etheno bridges based on NMR and X-ray crystallography. The all-syn diastereomer can be transformed into a molecular belt by inter- and intramolecular Diels–Alder reactions with a bifunctional building block. The molecular belt could function as a synthetic intermediate en route to a [11]cyclacene photoprecursor.
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Pöschl M, Gopi Sathi S, Stoček R, Kratina O. Rheometer Evidences for the Co-Curing Effect of a Bismaleimide in Conjunction with the Accelerated Sulfur on Natural Rubber/Chloroprene Rubber Blends. Polymers (Basel) 2021; 13:polym13091510. [PMID: 34067201 PMCID: PMC8125835 DOI: 10.3390/polym13091510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/03/2022] Open
Abstract
The rheometer curing curves of neat natural rubber (NR) and neat chloroprene rubber (CR) with maleide F (MF) exhibit considerable crosslinking torque at 180 °C. This indicates that MF can crosslink both these rubbers via Alder-ene reactions. Based on this knowledge, MF has been introduced as a co-crosslinking agent for a 50/50 blend of NR and CR in conjunction with accelerated sulfur. The delta (Δ) torque obtained from the curing curves of a blend with the addition of 1 phr MF was around 62% higher than those without MF. As the content of MF increased to 3 phr, the Δ torque was further raised to 236%. Moreover, the mechanical properties, particularly the tensile strength of the blend with the addition of 1 phr MF in conjunction with the accelerated sulfur, was around 201% higher than the blend without MF. The overall tensile properties of the blends cured with MF were almost retained even after ageing the samples at 70 °C for 72 h. This significant improvement in the curing torque and the tensile properties of the blends indicates that MF can co-crosslink between NR and CR via the Diels–Alder reaction.
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Ponomarev SA, Larkovich RV, Aldoshin AS, Tabolin AA, Ioffe SL, Groß J, Opatz T, Nenajdenko VG. Diels-Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes. Beilstein J Org Chem 2021; 17:283-292. [PMID: 33564337 PMCID: PMC7849230 DOI: 10.3762/bjoc.17.27] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/13/2021] [Indexed: 01/31/2023] Open
Abstract
The Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic 1,3-dienes was investigated. A series of novel monofluorinated norbornenes was prepared in up to 97% yield. The reaction with 1,3-cyclohexadiene permits the preparation of monofluorinated bicyclo[2.2.2]oct-2-enes. The kinetic data of the reactions with 1,3-cyclopentadiene and 1,3-cyclohexadiene were used to calculate activation parameters. Furthermore, the synthetic utility of the cycloadducts obtained was demonstrated.
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Affiliation(s)
- Savva A Ponomarev
- Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991, Russian Federation
| | - Roman V Larkovich
- Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991, Russian Federation
| | - Alexander S Aldoshin
- Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991, Russian Federation
| | - Andrey A Tabolin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences Leninsky prosp. 47, Moscow 119991, Russian Federation
| | - Sema L Ioffe
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences Leninsky prosp. 47, Moscow 119991, Russian Federation
| | - Jonathan Groß
- Department of Chemistry Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Till Opatz
- Department of Chemistry Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Valentine G Nenajdenko
- Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1, Moscow, 119991, Russian Federation
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46
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Kolaříková V, Rybáčková M, Svoboda M, Kvíčala J. Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2 H-pyrans. Beilstein J Org Chem 2020; 16:2757-2768. [PMID: 33224302 PMCID: PMC7670115 DOI: 10.3762/bjoc.16.226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/28/2020] [Indexed: 11/23/2022] Open
Abstract
The prochiral 4-(allyloxy)hepta-1,6-diynes, optionally modified in the positions 1 and 7 with an alkyl or ester group, undergo a chemoselective ring-closing enyne metathesis yielding racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans. Among the catalysts tested, Grubbs 1st generation precatalyst in the presence of ethene (Mori conditions) gave superior results compared to the more stable Grubbs or Hoveyda-Grubbs 2nd generation precatalysts. This is probably caused by a suppression of the subsequent side-reactions of the enyne metathesis product with ethene. On the other hand, the 2nd generation precatalysts gave better yields in the absence of ethene. The metathesis products, containing both a triple bond and a conjugated system, can be successfully orthogonally modified. For example, the metathesis product of 5-(allyloxy)nona-2,7-diyne reacted chemo- and stereoselectively in a Diels-Alder reaction with N-phenylmaleimide affording the tricyclic products as a mixture of two separable diastereoisomers, the configuration of which was estimated by DFT computations. The reported enediyne metathesis paves the way to the enantioselective enyne metathesis yielding chiral building blocks for compounds with potential biological activity, e.g., norsalvinorin or cacospongionolide B.
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Affiliation(s)
- Viola Kolaříková
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Markéta Rybáčková
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Martin Svoboda
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Jaroslav Kvíčala
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
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Van Craen D, Begall J, Großkurth J, Himmel L, Linnenberg O, Isaak E, Albrecht M. Hierarchically assembled helicates as reaction platform - from stoichiometric Diels-Alder reactions to enamine catalysis. Beilstein J Org Chem 2020; 16:2338-2345. [PMID: 33029252 PMCID: PMC7522461 DOI: 10.3762/bjoc.16.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/10/2020] [Indexed: 11/23/2022] Open
Abstract
The stereoselectivity of a Diels-Alder reaction within the periphery of hierarchically assembled titanium(IV) helicates formed from mixtures of achiral, reactive and chiral, unreactive ligands was investigated in detail. Following the pathway of the chiral induction, the chiral ligands, solvents as well as substituents at the dienophile were carefully varied. Based on the results of the stoichiometric reaction, a secondary amine-catalyzed nitro-Michael reaction is performed as well which afforded reasonable diastereoselectivities.
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Affiliation(s)
- David Van Craen
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Jenny Begall
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Johannes Großkurth
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Leonard Himmel
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Oliver Linnenberg
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Elisabeth Isaak
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Markus Albrecht
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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48
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Asahara H, Hiraishi M, Nishiwaki N. One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes. Beilstein J Org Chem 2020; 16:1830-1836. [PMID: 32765798 PMCID: PMC7385393 DOI: 10.3762/bjoc.16.150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/15/2020] [Indexed: 12/28/2022] Open
Abstract
β-Nitrostyrenes underwent a Diels-Alder reaction with Danishefsky's diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated-5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated-4-nitrophenols. The reaction of nitrostyrenes with Danishefsky's diene could be conducted in one pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group, e.g., a thienyl group could be introduced into the nitrophenol framework.
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Affiliation(s)
- Haruyasu Asahara
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan
- Research Center for Molecular Design, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamadaoka 1-6, Suita, Osaka 565-0871, Japan
| | - Minami Hiraishi
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan
| | - Nagatoshi Nishiwaki
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan
- Research Center for Molecular Design, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan
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Wu W, Narayana Kurup S, Ellingford C, Li J, Wan C. Coupling Dynamic Covalent Bonds and Ionic Crosslinking Network to Promote Shape Memory Properties of Ethylene-vinyl Acetate Copolymers. Polymers (Basel) 2020; 12:E983. [PMID: 32340183 DOI: 10.3390/polym12040983] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/20/2020] [Accepted: 04/20/2020] [Indexed: 12/05/2022] Open
Abstract
Dynamic crosslinking networks based on Diels–Alder (DA) chemistry and ionic interactions were introduced to maleic anhydride modified ethylene-vinyl acetate copolymer (mEVA) via in situ melt processing. The dual dynamic crosslinking networks were characterized by temperature-dependent FTIR, and the effects on the shape memory properties of mEVA were evaluated with dynamic mechanical thermal analysis and cyclic tensile testing. A crosslinking density was achieved at 2.36 × 10−4 mol·cm−3 for DA-crosslinked mEVA; as a result, the stress at 100% extension was increased from 3.8 to 5.6 MPa, and tensile strength and elongation at break were kept as high as 30.3 MPa and 486%, respectively. The further introduction of 10 wt % zinc methacrylate increased the dynamic crosslinking density to 3.74 × 10−4 mol·cm−3 and the stress at 100% extension to 9.0 MPa, while providing a tensile strength of 28.4 MPa and strain at break of 308%. The combination of reversible DA covalent crosslinking and ionic network in mEVA enabled a fixing ratio of 76.4% and recovery ratio of 99.4%, exhibiting an enhanced shape memory performance, especially at higher temperatures. The enhanced shape memory and mechanical performance of the dual crosslinked mEVA showed promising reprocessing and recycling abilities of the end-of-life products in comparison to traditional peroxide initiated covalent crosslinked counterparts.
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50
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Sain S, Åkesson D, Skrifvars M. Synthesis and Properties of Thermosets from Tung Oil and Furfuryl Methacrylate. Polymers (Basel) 2020; 12:polym12020258. [PMID: 31979058 PMCID: PMC7077211 DOI: 10.3390/polym12020258] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 11/22/2022] Open
Abstract
This work focuses on the development of cross-linked polymer from a highly unsaturated vegetable oil, tung oil (TO) and a bio-based acrylate, furfuryl methacrylate (FMA). The presence of a high degree of unsaturated carbon-carbon bonding in TO makes it a suitable precursor for polymer synthesis. Using this advantage of TO, in this work, we have synthesised a cross-linked polymer from TO and FMA through free radical polymerisation followed by Diels–Alder (DA) reaction. Successful incorporation of both of the raw materials and the two chemical reactions was shown using Fourier-transform infrared (FTIR) and Raman spectroscopy. The development of cross-linked structure was analysed through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA).
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