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Teixeira MG, Alvarenga ES. Characterization of novel isobenzofuranones by DFT calculations and 2D NMR analysis. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:623-631. [PMID: 26811211 DOI: 10.1002/mrc.4411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 06/05/2023]
Abstract
Phthalides are frequently found in naturally occurring substances and exhibit a broad spectrum of biological activities. In the search for compounds with insecticidal activity, phthalides have been used as versatile building blocks for the syntheses of novel potential agrochemicals. In our work, the Diels-Alder reaction between furan-2(5H)-one and cyclopentadiene was used successfully to obtain (3aR,4S,7R,7aS)-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1(3H)-one and (3aS,4R,7S,7aR)-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1(3H)-one (2) and (3aS,4S,7R,7aR)-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1(3H)-one and (3aR,4R,7S,7aS)-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1(3H)-one (3). The endo adduct (2) was brominated to afford (3aR,4R,5R,7R,7aS,8R)-5,8-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one and (3aS,4S,5S,7S,7aR,8S)-5,8-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one (4) and (3aS,4R,5R,6S,7S,7aR)-5,6-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one and (3aR,4S,5S,6R,7R,7aS)-5,6-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one (5). Following the initial analysis of the NMR spectra and the proposed two novel unforeseen products, we have decided to fully analyze the classical and non-classical assay structures with the aid of computational calculations. Computation to predict the (13) C and (1) H chemical shifts for mean absolute error analyses have been carried out by gauge-including atomic orbital method at M06-2X/6-31+G(d,p) and B3LYP/6-311+G(2d,p) levels of theory for all viable conformers. Characterization of the novel unforeseen compounds (4) and (5) were not possible by employing only the experimental NMR data; however, a more conclusive structural identification was performed by comparing the experimental and theoretical (1) H and (13) C chemical shifts by mean absolute error and DP4 probability analyses. Copyright © 2016 John Wiley & Sons, Ltd.
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Bertrand R, Hamp I, Brönstrup M, Weck R, Lukacevic M, Polyak A, Ross TL, Gotthardt M, Plettenburg O, Derdau V. Synthesis of GPR40 targeting 3 H- and 18 F-probes towards selective beta cell imaging. J Labelled Comp Radiopharm 2016; 59:604-610. [PMID: 27282912 DOI: 10.1002/jlcr.3412] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 04/11/2016] [Accepted: 05/09/2016] [Indexed: 11/07/2022]
Abstract
Diabetes affects an increasing number of patients worldwide and is responsible for a significant rise in healthcare expenses. Imaging of β-cells in vivo is expected to contribute to an improved understanding of the underlying pathophysiology, improved diagnosis, and development of new treatment options for diabetes. Here, we describe the first radiosyntheses of [3 H]-TAK875 and [18 F]-TAK875 derivatives to be used as β-cell imaging probes addressing the free fatty acid receptor 1 (FFAR1/GPR40). The fluorine-labeled derivative showed similar agonistic activity as TAK875 in a functional assay. The radiosynthesis of the 18 F-labelled tracer 2a was achieved with 16.7 ± 5.7% radiochemical yield in a total synthesis time of 60-70 min.
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Schwenk D, Brandt P, Blanchette RA, Nett M, Hoffmeister D. Unexpected Metabolic Versatility in a Combined Fungal Fomannoxin/Vibralactone Biosynthesis. JOURNAL OF NATURAL PRODUCTS 2016; 79:1407-1414. [PMID: 27104866 DOI: 10.1021/acs.jnatprod.6b00147] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The secondary metabolome of an undescribed stereaceous basidiomycete (BY1) was investigated for bioactive compounds. Along with a known fomannoxin derivative and two known vibralactones, we here describe three new compounds of these natural product families, whose structures were elucidated using 1D and 2D NMR spectroscopy and high-resolution mass spectrometry. The new compound vibralactone S (4) shows a 3,6-substituted oxepin-2(7H)-one ring system, which is unprecedented for the vibralactone/fomannoxin class of compounds. Stable isotope labeling established a biosynthetic route that is dissimilar to the two published cascades of oxepinone formation. Another new compound, the antifungal methyl seco-fomannoxinate (6), features a 2-methylprop-1-enyl ether moiety, which is only rarely observed with natural products. The structure of 6 was confirmed by total synthesis. (13)C-labeling experiments revealed that the unusual 2-methylprop-1-enyl ether residue derives from an isoprene unit. The diversity of BY1's combined fomannoxin/vibralactone metabolism is remarkable in that these compound families, although biosynthetically related, usually occur in different organisms.
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Yu W, Coburn CA, Nair AG, Wong M, Tong L, Dwyer MP, Hu B, Zhong B, Hao J, Yang DY, Selyutin O, Jiang Y, Rosenblum SB, Kim SH, Lavey BJ, Zhou G, Rizvi R, Shankar BB, Zeng Q, Chen L, Agrawal S, Carr D, Rokosz L, Liu R, Curry S, McMonagle P, Ingravallo P, Lahser F, Asante-Appiah E, Nomeir A, Kozlowski JA. Alkyl substituted aminal derivatives of HCV NS5A inhibitor MK-8742. Bioorg Med Chem Lett 2016; 26:3800-5. [PMID: 27282742 DOI: 10.1016/j.bmcl.2016.05.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 11/18/2022]
Abstract
HCV NS5A inhibitors have demonstrated impressive in vitro potency profiles in HCV replicon assays and robust HCV RNA titer reduction in the clinic making them attractive components for inclusion in an all oral fixed dose combination regimen for the treatment of HCV infection. Herein we describe our continued research efforts around the alkyl "Z group" modification of the tetracyclic indole-based NS5A inhibitor MK-8742, which led to the discovery of a series of potent NS5A inhibitors. Compounds 10 and 19 are of particular interests since they are as potent as our previous leads and have much improved rat pharmacokinetic profiles.
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Cole AL, Hossain S, Cole AM, Phanstiel O. Synthesis and bioevaluation of substituted chalcones, coumaranones and other flavonoids as anti-HIV agents. Bioorg Med Chem 2016; 24:2768-76. [PMID: 27161874 DOI: 10.1016/j.bmc.2016.04.045] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/15/2016] [Accepted: 04/21/2016] [Indexed: 01/26/2023]
Abstract
A series of chalcone, flavone, coumaranone and other flavonoid compounds were screened for their anti HIV-1 activity in two cell culture models using TZM-bl and PM1 cells. Within the systems evaluated, the most promising compounds contained either an α- or β-hydroxy-carbonyl motif within their structure (e.g., 8 and 9). Efficacious substituents were identified and used to design new HIV inhibitors with increased potency and lower cytotoxicity. Of the scaffolds evaluated, specific chalcones were found to provide the best balance between anti-HIV potency and low host cell toxicity. Chalcone 8l was shown to inhibit different clinical isolates of HIV in a dose-dependent manner (e.g., IC50 typically⩽5μM). Inhibition of HIV infection experiments using TZM-bl cells demonstrated that chalcone 8l and flavonol 9c had IC50 values of 4.7μM and 10.4μM, respectively. These insights were used to design new chalcones 8o and 8p. Rewardingly, chalcones 8o and 8p (at 10μM) each gave >92% inhibition of viral propagation without impacting PM1 host cell viability. Inhibition of viral propagation significantly increased (60-90%) when PM1 cells were pre-incubated with chalcone 8o, but not with the related flavonol 9c. These results suggested that chalcone 8o may be of value as both a HIV prophylactic and therapy. In summary, O-benzyl-substituted chalcones were identified as promising anti-HIV agents for future investigation.
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Lu D, Wei HX, Zhang J, Gu Y, Osenkowski P, Ye W, Selkoe DJ, Wolfe MS, Augelli-Szafran CE. Part 1: Notch-sparing γ-secretase inhibitors: The identification of novel naphthyl and benzofuranyl amide analogs. Bioorg Med Chem Lett 2016; 26:2129-32. [PMID: 27013392 DOI: 10.1016/j.bmcl.2016.03.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 01/23/2023]
Abstract
γ-Secretase is one of two proteases directly involved in the production of the amyloid β-peptide (Aβ), which is pathogenic in Alzheimer's disease. Inhibition of γ-secretase to suppress the production of Aβ should not block processing of one of its alternative substrates, Notch1 receptors, as interference with Notch1 signaling leads to severe toxic effects. In the course of our studies to identify γ-secretase inhibitors with selectivity for APP over Notch, 1 [3-(benzyl(isopropyl)amino)-1-(naphthalen-2-yl)propan-1-one] was found to inhibit γ-secretase-mediated Aβ production without interfering with γ-secretase-mediated Notch processing in purified enzyme assays. As 1 is chemically unstable, efforts to increase the stability of this compound led to the identification of 2 [naphthalene-2-carboxylic acid benzyl-isopropyl-amide] which showed similar biological activity to compound 1. Synthesis and evaluation of a series of amide analogs resulted in benzofuranyl amide analogs that showed promising Notch-sparing γ-secretase inhibitory effects. This class of compounds may serve as a novel lead series for further study in the development of γ-secretase inhibitors.
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Qi C, Xiong Y, Eschenbrenner-Lux V, Cong H, Porco JA. Asymmetric Syntheses of the Flavonoid Diels-Alder Natural Products Sanggenons C and O. J Am Chem Soc 2016; 138:798-801. [PMID: 26735066 PMCID: PMC4863937 DOI: 10.1021/jacs.5b12778] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Metal-catalyzed, double Claisen rearrangement of a bis-allyloxyflavone has been utilized to enable a concise synthesis of the hydrobenzofuro[3,2-b]chromenone core structure of the natural products sanggenon A and sanggenol F. In addition, catalytic, enantioselective [4+2] cycloadditions of 2'-hydroxychalcones have been accomplished using B(OPh)3/BINOL complexes. Asymmetric syntheses of the flavonoid Diels-Alder natural products sanggenons C and O have been achieved employing a stereodivergent reaction of a racemic mixture (stereodivergent RRM) involving [4+2] cycloaddition.
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Romagnoli R, Baraldi PG, Prencipe F, Lopez-Cara C, Rondanin R, Simoni D, Hamel E, Grimaudo S, Pipitone RM, Meli M, Tolomeo M. Novel iodoacetamido benzoheterocyclic derivatives with potent antileukemic activity are inhibitors of STAT5 phosphorylation. Eur J Med Chem 2016; 108:39-52. [PMID: 26629859 PMCID: PMC4724257 DOI: 10.1016/j.ejmech.2015.11.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/06/2015] [Accepted: 11/16/2015] [Indexed: 12/29/2022]
Abstract
Signal Transducer and Activator of Transcription 5 (STAT5) protein, a component of the STAT family of signaling proteins, is considered to be an attractive therapeutic target because of its involvement in the progression of acute myeloid leukemia. In an effort to discover potent molecules able to inhibit the phosphorylation-activation of STAT5, twenty-two compounds were synthesized and evaluated on the basis of our knowledge of the activity of 2-(3',4',5'-trimethoxybenzoyl)-3-iodoacetamido-6-methoxy benzo[b]furan derivative 1 as a potent STAT5 inhibitor. Most of these molecules, structurally related to compound 1, were characterized by the presence of a common 3',4',5'-trimethoxybenzoyl moiety at the 2-position of different benzoheterocycles such as benzo[b]furan, benzo[b]thiophene, indole and N-methylindole. Effects on biological activity of the iodoacetamido group and of different moieties (methyl and methoxy) at the C-3 to C-7 positions were examined. In the series of benzo[b]furan derivatives, moving the iodoacetylamino group from the C-4 to the C-5 or C-6 positions did not significantly affect antiproliferative activity. Compounds 4, 15, 20 and 23 blocked STAT5 signals and induced apoptosis of K562 BCR-ABL positive cells. For compound 23, the trimethoxybenzoyl moiety at the 2-position of the benzo[b]furan core was not essential for potent inhibition of STAT5 activation.
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Han Y, Liu W, Pan W, Wang P, Tian Z, Zhao Y, Wang M, Chen X, Liao X, Zheng M. Formation Pathways of Mono- to Octa-Chlorinated Dibenzo-p-dioxins and Dibenzofurans in Main Organochemical Industries. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:10945-10950. [PMID: 26301518 DOI: 10.1021/acs.est.5b02683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The concentrations and formation pathways of mono- to octa-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were investigated in main organochemical industries. High levels of PCDDs and PCDFs were detected. The total concentrations of 27 PCDD/F congeners in chloranil, 2,4-D, and 1,4-dichlorobenzene were 5302397 ± 8944449, 20963 ± 15908, and 242 ± 67 pg g(-1), respectively, and the less-chlorinated PCDD/F levels were 12006 ± 20155, 9536 ± 5594, and 195 ± 94 pg g(-1), respectively. The distribution trends of less and more chlorinated PCDD/Fs were similar in different chemical plants because of their similar formation pathways, which may also be related to the degree of chlorination of chemical products and purification processes. 1,2,3,4-TeCDF and 2,4,8-TrCDF were selected as model molecules to calculate the bond dissociation energy, showing that 2-MCDF, 3-MCDF, and 2,8-DCDF are more easily formatted as shown by the analytical results. The formation pathways of less to more chlorinated PCDFs are proposed to explain why 2-MoCDF, 2,8-DiCDF, 2,4,8-TrCDF, and 2,3,4,7,8-PeCDF are the dominant congeners and to explain why 2,3,4,7,8-PeCDF is the largest contributor of I-TEQs in most studies.
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Shi X, Yu W, Xu F, Zhang Q, Hu J, Wang W. PBCDD/F formation from radical/radical cross-condensation of 2-Chlorophenoxy with 2-Bromophenoxy, 2,4-Dichlorophenoxy with 2,4-Dibromophenoxy, and 2,4,6-Trichlorophenoxy with 2,4,6-Tribromophenoxy. JOURNAL OF HAZARDOUS MATERIALS 2015; 295:104-111. [PMID: 25897691 DOI: 10.1016/j.jhazmat.2015.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 03/25/2015] [Accepted: 04/02/2015] [Indexed: 06/04/2023]
Abstract
Quantum chemical calculations were carried out to investigate the homogeneous gas-phase formation of mixed polybrominated/chlorinated dibenzo-p-dioxins/benzofurans (PBCDD/Fs) from the cross-condensation of 2-chlorophenoxy radical (2-CPR) with 2-bromophenoxy radical (2-BPR), 2,4-dichlorophenoxy radical (2,4-DCPR) with 2,4-dibromophenoxy radical (2,4-DBPR), and 2,4,6-trichlorophenoxy radical (2,4,6-TCPR) with 2,4,6-tribromophenoxy radical (2,4,6-TBPR). The geometrical parameters and vibrational frequencies were calculated at the MPWB1K/6-31+G(d,p) level, and single-point energy calculations were performed at the MPWB1K/6-311+G(3df,2p) level of theory. The rate constants of the crucial elementary reactions were evaluated by the canonical variational transition-state (CVT) theory with the small curvature tunneling (SCT) correction over a wide temperature range of 600-1200K. Studies show that the substitution pattern of halogenated phenols not only determines the substitution pattern of the resulting PBCDD/Fs, but also has a significant influence on the formation mechanism of PBCDD/Fs, especially on the coupling of the halogenated phenoxy radicals.
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Li J, Grillo AS, Burke MD. From synthesis to function via iterative assembly of N-methyliminodiacetic acid boronate building blocks. Acc Chem Res 2015; 48:2297-307. [PMID: 26200460 PMCID: PMC4688257 DOI: 10.1021/acs.accounts.5b00128] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The study and optimization of small molecule function is often impeded by the time-intensive and specialist-dependent process that is typically used to make such compounds. In contrast, general and automated platforms have been developed for making peptides, oligonucleotides, and increasingly oligosaccharides, where synthesis is simplified to iterative applications of the same reactions. Inspired by the way natural products are biosynthesized via the iterative assembly of a defined set of building blocks, we developed a platform for small molecule synthesis involving the iterative coupling of haloboronic acids protected as the corresponding N-methyliminodiacetic acid (MIDA) boronates. Here we summarize our efforts thus far to develop this platform into a generalized and automated approach for small molecule synthesis. We and others have employed this approach to access many polyene-based compounds, including the polyene motifs found in >75% of all polyene natural products. This platform further allowed us to derivatize amphotericin B, the powerful and resistance-evasive but also highly toxic last line of defense in treating systemic fungal infections, and thereby understand its mechanism of action. This synthesis-enabled mechanistic understanding has led us to develop less toxic derivatives currently under evaluation as improved antifungal agents. To access more Csp(3)-containing small molecules, we gained a stereocontrolled entry into chiral, non-racemic α-boryl aldehydes through the discovery of a chiral derivative of MIDA. These α-boryl aldehydes are versatile intermediates for the synthesis of many Csp(3) boronate building blocks that are otherwise difficult to access. In addition, we demonstrated the utility of these types of building blocks in accessing pharmaceutically relevant targets via an iterative Csp(3) cross-coupling cycle. We have further expanded the scope of the platform to include stereochemically complex macrocyclic and polycyclic molecules using a linear-to-cyclized strategy, in which Csp(3) boronate building blocks are iteratively assembled into linear precursors that are then cyclized into the cyclic frameworks found in many natural products and natural product-like structures. Enabled by the serendipitous discovery of a catch-and-release protocol for generally purifying MIDA boronate intermediates, the platform has been automated. The synthesis of 14 distinct classes of small molecules, including pharmaceuticals, materials components, and polycyclic natural products, has been achieved using this new synthesis machine. It is anticipated that the scope of small molecules accessible by this platform will continue to expand via further developments in building block synthesis, Csp(3) cross-coupling methodologies, and cyclization strategies. Achieving these goals will enable the more generalized synthesis of small molecules and thereby help shift the rate-limiting step in small molecule science from synthesis to function.
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Masaki S, Kii I, Sumida Y, Kato-Sumida T, Ogawa Y, Ito N, Nakamura M, Sonamoto R, Kataoka N, Hosoya T, Hagiwara M. Design and synthesis of a potent inhibitor of class 1 DYRK kinases as a suppressor of adipogenesis. Bioorg Med Chem 2015; 23:4434-4441. [PMID: 26145823 DOI: 10.1016/j.bmc.2015.06.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/05/2015] [Accepted: 06/06/2015] [Indexed: 12/28/2022]
Abstract
Dysregulation of dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) has been demonstrated in several pathological conditions, including Alzheimer's disease and cancer progression. It has been recently reported that a gain of function-mutation in the human DYRK1B gene exacerbates metabolic syndrome by enhancing obesity. In the previous study, we developed an inhibitor of DYRK family kinases (INDY) and demonstrated that INDY suppresses the pathological phenotypes induced by overexpression of DYRK1A or DYRK1B in cellular and animal models. In this study, we designed and synthesized a novel inhibitor of DYRK family kinases based on the crystal structure of the DYRK1A/INDY complex by replacing the phenol group of INDY with dibenzofuran to produce a derivative, named BINDY. This compound exhibited potent and selective inhibitory activity toward DYRK family kinases in an in vitro assay. Furthermore, treatment of 3T3-L1 pre-adipocytes with BINDY hampered adipogenesis by suppressing gene expression of the critical transcription factors PPARγ and C/EBPα. This study indicates the possibility of BINDY as a potential drug for metabolic syndrome.
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Bolat Z, Kırılmış C, Kurt A. Synthesis, Characterization and Thermal Decomposition Kinetics of a Novel Benzofuran Ketoxime Derived Polymer. Acta Chim Slov 2015; 62:428-36. [PMID: 26085427 DOI: 10.17344/acsi.2014.900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A novel benzofuran ketoxime derived polymer, poly(benzofuran-2-yl-methylketoxime-O-methacrylate) [poly(BMKMA], was firstly synthesized by free radical polymerization method. Its thermal degradation studies were performed by thermogravimetric analysis (TGA) in order to determine the actual reaction mechanisms of the decomposition process. The activation energy of the solid-state process was determined using Flynn-Wall-Ozawa method, which resulted to be 235.94 kJ/mol. The activation energies of different mechanism models were determined by Coats-Redfern, Madhusudanan and Van Krevelen kinetic methods. Compared with the Ozawa method, the actual reaction mechanism obeyed deceleration type, phase boundary controlled reaction (R1).
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Yang W, Liu Y, Zhang S, Cai Q. Copper-Catalyzed Intramolecular Desymmetric Aryl C-O Coupling for the Enantioselective Construction of Chiral Dihydrobenzofurans and Dihydrobenzopyrans. Angew Chem Int Ed Engl 2015; 54:8805-8. [PMID: 26060986 DOI: 10.1002/anie.201503882] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Indexed: 01/08/2023]
Abstract
O-Heterocyclic structures such as 2,3-dihydrobenzofurans are key motifs in many natural compounds and pharmaceuticals. Enantioselective formation of chiral dihydrobenzofurans and analogues was achieved through a copper-catalyzed desymmetrization strategy with a chiral cyclic 1,2-diamine. A broad range of substrates are compatible with this Cu(I)-diamine catalytic system and afford the desired coupling products with chiral tertiary or quaternary carbon centers in high yields and good to excellent enantioselectivities under mild conditions.
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Kuramochi K, Tsubaki K. Synthesis and structural characterization of natural benzofuranoids. JOURNAL OF NATURAL PRODUCTS 2015; 78:1056-1066. [PMID: 25906402 DOI: 10.1021/np5010483] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The synthesis of ustusoranes A, B, and E, pergillin, dihydropergillin, (±)-penicisochroman A, and (-)-brassicadiol, starting from optically active (R)-benzolactone, is described. The synthesis of ustusoranes A and E established the absolute configurations of these natural products. The synthesis of pergillin and (±)-penicisochroman A led to the structural revision of aspergiones E and F. This study clearly indicates that (R)-benzolactone is a potential intermediate in the synthesis of natural benzofuranoids.
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López-Frías G, Camacho-Dávila AA, Chávez-Flores D, Zaragoza-Galán G, Ramos-Sánchez VH. Synthesis of a Functionalized Benzofuran as a Synthon for Salvianolic Acid C Analogues as Potential LDL Antioxidants. Molecules 2015; 20:8654-65. [PMID: 26007172 PMCID: PMC6272376 DOI: 10.3390/molecules20058654] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/07/2015] [Indexed: 12/27/2022] Open
Abstract
A palladium mediated synthesis of a common synthon for the syntheses of antioxidant analogues of naturally occurring salvianolic acids is presented. The synthetic route may be used to obtain analogues with a balanced lipophilicity/hydrophilicity which may result in potentially interesting LDL antioxidants for the prevention of cardiovascular diseases.
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Abstract
Short total syntheses of arnottin I and II were accomplished in 5 and 6 steps, respectively. A sesamol-benzyne cycloaddition with a 3-furyl-benzoate followed by regiospecific lactonization provided rapid, large-scale access to the core of arnottin I. Saponification of arnottin I and hypervalent iodide mediated spirocyclization provided an efficient and direct preparation of racemic arnottin II.
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Kosmalski T, Kutkowska J, Gzella AK, Nowakiewicz A. NEW HETEROCYCLIC OXIME ETHERS OF 1-(BENZOFURAN-2-YL)ETHAN- 1-ONE AND THEIR ANTIMICROBIAL ACTIVITY. ACTA POLONIAE PHARMACEUTICA 2015; 72:289-295. [PMID: 26642679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this study, some O-benzyl (benzofuran-2-yl)ethan-1-one ether oximes were synthesized starting from 2-acetylbenzofuran. The structure elucidation of the compounds was performed by IR, 1H-NMR and 13C-NMR spectra. Antimicrobial activities of the compounds were examined and notable activity was observed.
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Stone S, Lajkiewicz NJ, Whitesell L, Hilmy A, Porco JA. Biomimetic kinetic resolution: highly enantio- and diastereoselective transfer hydrogenation of aglain ketones to access flavagline natural products. J Am Chem Soc 2015; 137:525-30. [PMID: 25514979 PMCID: PMC4304436 DOI: 10.1021/ja511728b] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Indexed: 02/06/2023]
Abstract
We have previously reported asymmetric syntheses and absolute configuration assignments of the aglains (+)-ponapensin and (+)-elliptifoline and proposed a biosynthetic kinetic resolution process to produce enantiomeric rocaglamides and aglains. Herein, we report a biomimetic approach for the synthesis of enantiomerically enriched aglains and rocaglamides via kinetic resolution of a bridged ketone utilizing enantioselective transfer hydrogenation. The methodology has been employed to synthesize and confirm the absolute stereochemistries of the pyrimidone rocaglamides (+)-aglaiastatin and (-)-aglaroxin C. Additionally, the enantiomers and racemate of each metabolite were assayed for inhibition of the heat-shock response, cytotoxicity, and translation inhibition.
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Goudarshivananavar BC, Vigneshwaran V, Dharmappa KK, Pramod SN. Pharmacological Potential of Tetrahydrofurano/Pyrano Quinoline and Benzo[b]furoindolyl Derivatives in Acute Inflammation, Pain and Oxidative Stress. Antiinflamm Antiallergy Agents Med Chem 2015; 13:165-173. [PMID: 25515170 DOI: 10.2174/1871523014666141217125732] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/04/2014] [Accepted: 12/15/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVE Investigation of the pharmacological potential of Tetrahydrofurano/pyrano quinoline and Benzo [b]furoindolyl derivatives in acute inflammation, pain and oxidative stress. METHODS Tetrahydrofurano/ pyrano quinoline and Benzo[b]furoindolyl were evaluated for anti-inflammatory activity by carrageenan-induced hind paw edema in rats. Analgesic activity in mice was assessed by both peripheral and central analgesic models. The free radical scavenging activity of the synthetic compound was analyzed by the in vivo antioxidant assays, by measuring the antioxidant enzymes such as Superoxide dismutase (SOD), Catalase and Peroxidase from the liver homogenate and the in vitro antioxidant activity was evaluated by DPPH photometric assay, Hydroxyl radical scavenging and Lipid Peroxidation assay. RESULTS The compounds had substantially inhibited the inflammation induced by subcutaneous carrageenan injection. The same compounds had demonstrated remarkable central and peripheral analgesic activity with potent free radical scavenging activity as evident from both in vitro and in vivo antioxidant assays. CONCLUSION Tetrahydrofurano/pyrano quinoline and Benzo[b]furoindolyl derivatives exhibit varied pharmacological activities that include anti-inflammatory, analgesic and antioxidant activity.
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Altarawneh M, Dlugogorski BZ. Formation of polybrominated dibenzofurans from polybrominated biphenyls. CHEMOSPHERE 2015; 119:1048-1053. [PMID: 25303667 DOI: 10.1016/j.chemosphere.2014.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/31/2014] [Accepted: 09/03/2014] [Indexed: 06/04/2023]
Abstract
Decades after phasing out their production and use, especially in the formulations of brominated flame retardants (BFRs), polybrominated biphenyls (PBBs) still pose serious environmental and health problems. The oxidation of PBB has been hypothesised as a pathway for the formation of the notorious polybrominated dibenzofurans (PBDFs) and their dispersion in the environment. However, the exact reaction corridor remains misunderstood, with the existing mechanisms predicting the reaction to proceed via a high energy process that involves the breakage of C-C linkage (∼118.0 kcal mol(-1)) and the subsequent formation of bromophenols molecules, where the latter are supposed to act as precursors for the formation of PBDFs (∼40.0-60.0 kcal mol(-1)). Herein, we show that PBBs produce PBDFs in a facile mechanism through a series of highly exothermic reactions (i.e., overall barriers reside 8.2-10.0 kcal mol(-1) below the entrance channel). Whilst the fate of the ROO-type intermediates in oxidation of all aromatics is to emit CO or CO2, PBDFs constitute the dominant products from the oxidation of PBBs. Initially formed R-OO adduct evolves in a very exoergic mechanism to yield PBDFs. In view of the facile oxidative transformation of PBBs into PBDFs, we conclude that, it is unsafe to dispose BFRs in oxidation processes, as this practice generates high yields of toxic PBDFs.
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Nguyen QV, Lan PDT, Thi HP, Vu VC, Le TN, Chau VM, Pham VC. Facile, protection-free, one-pot synthesis of aureusidin. Nat Prod Commun 2014; 9:1563-1566. [PMID: 25532281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
A new, reliable, and convenient protection-free one-pot method for the synthesis of aureusidin (1) is described. The present synthetic approach involves the condensation of 4,6-dihydroxybenzofuranone with 3,4-dihydroxybenzaldehyde in the presence of concentrated HCl to afford aureusidin (1) in good yield with high purity. This procedure offers a short and simple route for the preparation of aureusidin (1), a bioactive natural product from several vegetal species, as well as for synthesis of other aurones.
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Blum TR, Zhu Y, Nordeen SA, Yoon TP. Photocatalytic synthesis of dihydrobenzofurans by oxidative [3+2] cycloaddition of phenols. Angew Chem Int Ed Engl 2014; 53:11056-9. [PMID: 25155300 PMCID: PMC4220618 DOI: 10.1002/anie.201406393] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Indexed: 11/06/2022]
Abstract
We report a protocol for oxidative [3+2] cycloadditions of phenols and alkenes applicable to the modular synthesis of a large family of dihydrobenzofuran natural products. Visible-light-activated transition metal photocatalysis enables the use of ammonium persulfate as an easily handled, benign terminal oxidant. The broad range of organic substrates that are readily oxidized by photoredox catalysis suggests that this strategy may be applicable to a variety of useful oxidative transformations.
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Belmessieri D, de la Houpliere A, Calder EDD, Taylor JE, Smith AD. Stereodivergent organocatalytic intramolecular Michael addition/lactonization for the asymmetric synthesis of substituted dihydrobenzofurans and tetrahydrofurans. Chemistry 2014; 20:9762-9. [PMID: 24989672 PMCID: PMC4517160 DOI: 10.1002/chem.201402684] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Indexed: 11/19/2022]
Abstract
A stereodivergent asymmetric Lewis base catalyzed Michael addition/lactonization of enone acids into substituted dihydrobenzofuran and tetrahydrofuran derivatives is reported. Commercially available (S)-(-)-tetramisole hydrochloride gives products with high syn diastereoselectivity in excellent enantioselectivity (up to 99:1 d.r.syn/anti , 99 % eesyn ), whereas using a cinchona alkaloid derived catalyst gives the corresponding anti-diastereoisomers as the major product (up to 10:90 d.r.syn/anti , 99 % eeanti ).
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Ortuño N, Conesa JA, Moltó J, Font R. De novo synthesis of brominated dioxins and furans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:7959-7965. [PMID: 24946180 DOI: 10.1021/es501818d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
On the basis of laboratory experiments with model mixtures (active carbon+CuBr2 at different loads), this work studies the formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) by de novo synthesis. For the different samples, the temperature of the maximum carbon oxidation rate was determined by thermogravimetric analysis, and a kinetic model was proposed for the degradation of the materials in an oxidizing atmosphere (synthetic air). The effect of the addition of different amounts of CuBr2 was studied, finding that its presence accelerates the degradation of the carbonaceous structure in the presence of oxygen. The thermal degradation of the samples in air is satisfactorily described by a first-order single-reaction model. In addition, combustion runs of one of the mixtures (consisting of activated carbon+50 wt % CuBr2, pyrolyzed at 700 °C) were performed in a quartz horizontal laboratory furnace. The analysis of the emissions and the solid residue proved the formation of brominated dioxins and furans at 300, 400, and 500 °C, with a maximum yield at 300 °C (91.7 ng/g of total PBDD/Fs) and a higher bromination degree with increasing temperature.
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