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Ozsvár D, Bózsity N, Zupkó I, Szakonyi Z. Synthesis and Study of the Structure-Activity Relationship of Antiproliferative N-Substituted Isosteviol-Based 1,3-Aminoalcohols. Pharmaceuticals (Basel) 2024; 17:262. [PMID: 38399477 PMCID: PMC10893060 DOI: 10.3390/ph17020262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 02/25/2024] Open
Abstract
Starting from isosteviol, a series of diterpenoid 1,3-aminoalcohol derivatives were prepared via stereoselective transformations. The acid-catalysed hydrolysis and rearrangement of natural stevioside produced isosteviol, which was transformed into the key intermediate methyl ester. In the next step, an 1,3-aminoalcohol library was prepared by the reductive amination of the intermediate 3-hydroxyaldehyde obtained from isosteviol in a two-step synthesis. To study the effect of the carboxylate ester function at position 4, the free carboxylic acid, benzyl ester and acryloyl ester analogues were prepared as elongated derivatives in comparison with our earlier results in this field. The antiproliferative activity of compounds against human tumour cell lines (A2780, HeLa, MCF-7 and MDA-MB-231) was investigated. In our preliminary study, the 1,3-aminoalcohol function with N-benzyl or (1H-imidazol-1-yl)-propyl substitution and benzyl ester moiety seemed essential for the reliable antiproliferative activity. The results obtained could be a good starting point to further functionalisation towards more efficient antiproliferative diterpenes.
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Affiliation(s)
- Dániel Ozsvár
- Interdisciplinary Excellence Center, Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary;
| | - Noémi Bózsity
- Institute of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary; (N.B.); (I.Z.)
| | - István Zupkó
- Institute of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary; (N.B.); (I.Z.)
- Interdisciplinary Centre of Natural Products, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary
| | - Zsolt Szakonyi
- Interdisciplinary Excellence Center, Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary;
- Interdisciplinary Centre of Natural Products, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary
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Ozsvár D, Nagy V, Zupkó I, Szakonyi Z. Synthesis and Biological Application of Isosteviol-Based 1,3-Aminoalcohols. Int J Mol Sci 2021; 22:ijms222011232. [PMID: 34681892 PMCID: PMC8538607 DOI: 10.3390/ijms222011232] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 01/14/2023] Open
Abstract
Starting from isosteviol, a series of diterpenoid 1,3-aminoalcohol derivatives were stereoselectively synthesised. The acid-catalysed hydrolysis and rearrangement of natural stevioside gave isosteviol, which was transformed to the key intermediate methyl ester. In the next step, Mannich condensation of diterpenoid ketone, paraformaldehyde, and secondary amines resulted in the formation of 1,3-aminoketones with different stereoselectivities. During the Mannich condensation with dibenzylamine, an interesting N-benzyl → N-methyl substituent exchange was observed. Reduction of 1,3-aminoketones produced diastereoisomeric 1,3-aminoalcohols. Alternatively, aminoalcohols were obtained via stereoselective hydroxy-formylation, followed by oxime preparation, reduction, and finally, reductive alkylation of the obtained primary aminoalcohols. An alternative 1,3-aminoalcohol library was prepared by reductive amination of the intermediate 3-hydroxyaldehyde obtained from isosteviol in two-step synthesis. Cytotoxic activity of compounds against human tumour cell lines (A2780, SiHa, HeLa, MCF-7 and MDA-MB-231) was investigated. In our preliminary study, the 1,3-aminoalcohol function and N-benzyl substitution seemed to be essential for the reliable antiproliferative activity. To extend their application, a diterpenoid condensed with 2-phenylimino-1,3-thiazine and -1,3-oxazine was also attempted to prepare, but only formation of thioether intermediate was observed.
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Affiliation(s)
- Dániel Ozsvár
- Interdisciplinary Excellence Center, Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary;
| | - Viktória Nagy
- Department of Pharmacodynamics and Biopharmacy, University of Szeged, H-6720 Szeged, Hungary; (V.N.); (I.Z.)
| | - István Zupkó
- Department of Pharmacodynamics and Biopharmacy, University of Szeged, H-6720 Szeged, Hungary; (V.N.); (I.Z.)
- Interdisciplinary Centre of Natural Products, University of Szeged, H-6720 Szeged, Hungary
| | - Zsolt Szakonyi
- Interdisciplinary Excellence Center, Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary;
- Interdisciplinary Centre of Natural Products, University of Szeged, H-6720 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-546809
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Sharipova RR, Belenok MG, Garifullin BF, Sapunova AS, Voloshina AD, Andreeva OV, Strobykina IY, Skvortsova PV, Zuev YF, Kataev VE. Synthesis and anti-cancer activities of glycosides and glycoconjugates of diterpenoid isosteviol. MEDCHEMCOMM 2019; 10:1488-1498. [PMID: 31673312 PMCID: PMC6786240 DOI: 10.1039/c9md00242a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/20/2019] [Indexed: 11/21/2022]
Abstract
A series of glycosides and glycoconjugates of diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) with various monosaccharide residues were synthesized and their cytotoxicity against some human cancer and normal cell lines was assayed. Most of the synthesized compounds demonstrated moderate to significant cytotoxicity against human cancer cell lines M-HeLa and MCF-7. Three lead compounds exhibited selective cytotoxic activities against M-HeLa (IC50 = 10.0-15.1 μM) that were three times better than the cytotoxicity of the anti-cancer drug Tamoxifen (IC50 = 28.0 μM). Moreover, the lead compounds were not cytotoxic with respect to the normal human cell line Chang liver (IC50 > 100 μM), whereas Tamoxifen inhibited the viability of normal human Chang liver cells with an IC50 value of 46.0 μM. It was determined that the cytotoxicity of the lead compounds was due to induction of apoptosis proceeding along the mitochondrial pathway. The cytotoxic activity of the synthesized compounds substantially depended on the nature of the monosaccharide residue and its position, that is, whether the monosaccharide residue was attached directly to the isosteviol skeleton or was moved away from it by means of a polymethylene linker.
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Affiliation(s)
- Radmila R Sharipova
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Mayya G Belenok
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Bulat F Garifullin
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Anastasiya S Sapunova
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Alexandra D Voloshina
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Olga V Andreeva
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Irina Yu Strobykina
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
| | - Polina V Skvortsova
- Kazan Institute of Biochemistry and Biophysics , FRC Kazan Scientific Center , Russian Academy of Sciences , Lobachevsky Str., 2/31 , Kazan , 420111 , Russian Federation
| | - Yuriy F Zuev
- Kazan Institute of Biochemistry and Biophysics , FRC Kazan Scientific Center , Russian Academy of Sciences , Lobachevsky Str., 2/31 , Kazan , 420111 , Russian Federation
- Kazan State Power Engineering University , 51, Krasnoselskaya str. , Kazan , 420066 , Russian Federation
| | - Vladimir E Kataev
- Arbuzov Institute of Organic and Physical Chemistry , FRC Kazan Scientific Center , Russian Academy of Sciences , Arbuzov str., 8 , Kazan , 420088 , Russian Federation .
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Sharipova RR, Belenok MG, Strobykina IY, Kataev VE. Phosphorylated Glycoconjugates Based on Isosteviol, d-Arabinofuranose, and d-Ribofuranose. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1070428019040158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bioactivity Profile of the Diterpene Isosteviol and its Derivatives. Molecules 2019; 24:molecules24040678. [PMID: 30769819 PMCID: PMC6412665 DOI: 10.3390/molecules24040678] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 02/03/2019] [Accepted: 02/06/2019] [Indexed: 12/24/2022] Open
Abstract
Steviosides, rebaudiosides and their analogues constitute a major class of naturally occurring biologically active diterpene compounds. The wide spectrum of pharmacological activity of this group of compounds has developed an interest among medicinal chemists to synthesize, purify, and analyze more selective and potent isosteviol derivatives. It has potential biological applications and improves the field of medicinal chemistry by designing novel drugs with the ability to cope against resistance developing diseases. The outstanding advancement in the design and synthesis of isosteviol and its derivative has proved its effectiveness and importance in the field of medicinal chemical research. The present review is an effort to integrate recently developed novel drugs syntheses from isosteviol and potentially active pharmacological importance of the isosteviol derivatives covering the recent advances.
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Enzymatic production of steviol using a commercial β-glucosidase and preparation of its inclusion complex with γ-CD. J INCL PHENOM MACRO 2018. [DOI: 10.1007/s10847-018-0868-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wang M, Li H, Xu F, Gao X, Li J, Xu S, Zhang D, Wu X, Xu J, Hua H, Li D. Diterpenoid lead stevioside and its hydrolysis products steviol and isosteviol: Biological activity and structural modification. Eur J Med Chem 2018; 156:885-906. [DOI: 10.1016/j.ejmech.2018.07.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 12/17/2022]
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Tejedor D, Delgado-Hernández S, Carballo RM, Dapueto R, Mena-Rejón GJ, García-Tellado F. Diversifying Complexity by Domino Benzannulation of Polycyclic Natural Products. J Org Chem 2017; 82:5328-5336. [PMID: 28467064 DOI: 10.1021/acs.joc.7b00654] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Herein we describe a salicylaldehyde-annulation reaction as a plug and play toolkit to diversify the complexity of naturally occurring ketones. The protocol entails the transformation of the polycyclic natural ketone into its propargyl vinyl ether derivative (two synthetic steps) and its microwave-assisted imidazole-catalyzed domino rearrangement to generate the salicylaldehyde ring. This annexed unit allows further synthetic transformations: e.g., the installation of a pharmacophore module to generate natural product-pharmacophore hybrids endowed with unknown biological (pharmaceutical) annotations.
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Affiliation(s)
- David Tejedor
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas , Avda. Astrofísico Francisco Sánchez 3, 38 206 La Laguna, Tenerife, Islas Canarias, Spain
| | - Samuel Delgado-Hernández
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas , Avda. Astrofísico Francisco Sánchez 3, 38 206 La Laguna, Tenerife, Islas Canarias, Spain
| | - Rubén M Carballo
- Laboratorio de Química Farmacéutica, Facultad de Química, Universidad Autónoma de Yucatán , C. 43 No. 613 x C. 90 Col. Inalámbrica, C.P. 97069, Mérida, Yucatán, México
| | - Rosina Dapueto
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas , Avda. Astrofísico Francisco Sánchez 3, 38 206 La Laguna, Tenerife, Islas Canarias, Spain
| | - Gonzalo J Mena-Rejón
- Laboratorio de Química Farmacéutica, Facultad de Química, Universidad Autónoma de Yucatán , C. 43 No. 613 x C. 90 Col. Inalámbrica, C.P. 97069, Mérida, Yucatán, México
| | - Fernando García-Tellado
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas , Avda. Astrofísico Francisco Sánchez 3, 38 206 La Laguna, Tenerife, Islas Canarias, Spain
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Liu CJ, Yu SL, Liu YP, Dai XJ, Wu Y, Li RJ, Tao JC. Synthesis, cytotoxic activity evaluation and HQSAR study of novel isosteviol derivatives as potential anticancer agents. Eur J Med Chem 2016; 115:26-40. [DOI: 10.1016/j.ejmech.2016.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/26/2022]
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Synthesis and anticancer evaluation of complex unsaturated isosteviol-derived triazole conjugates. Future Med Chem 2015; 7:2419-28. [PMID: 26653151 DOI: 10.4155/fmc.15.158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND For the last two decades, diterpenoid isosteviol and its derivatives have gained significant attention for novel chemical transformation in the drug discovery field. RESULTS An efficient way towards the synthesis of structurally diverse isosteviol derivatives was described here employing unsaturated functionalities as attractive templates for further transformation such as epoxidation. These structurally diverse compounds exhibited promising cytotoxic activities on different types of cancer cell lines, leading to drug discovery derived from natural products for the treatment of cancer. CONCLUSION In this work, novel isosteviol derivatives with Michael acceptors were synthesized to expand the diversity and complexity of a class of isosteviol-derived triazole conjugates to facilitate the development of potential antitumor agents.
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Oxazolidinone derivatives: cytoxazone-linezolid hybrids induces apoptosis and senescence in DU145 prostate cancer cells. Eur J Med Chem 2014; 80:295-307. [PMID: 24793880 DOI: 10.1016/j.ejmech.2014.04.062] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/20/2014] [Accepted: 04/22/2014] [Indexed: 11/23/2022]
Abstract
In this study, we report the synthesis of novel oxazolidinone derivatives derived from linezolid 3 having p-methoxyphenyl group at C-4 position. In vitro evaluation for their anticancer activity toward cultured A549, DU145, HELA, and MCF7 were carried out. The series of compounds prepared displayed wide range of cytotoxicity in MTT assays (10-70 μM) across the cell lines tested. Of the all tested compounds 16 and 17 displayed good anticancer potential against A549 (lung) and DU145 (prostate) cancer cells. Further, to determine their anticancer potential, in the present study we have assessed effect of 17 on DU145 cells growth in in vitro assays. The results clearly demonstrated that the exposure of DU145 cells to 17 inhibits cell proliferation and induces apoptosis by activation of caspase-3 and -9. Long term exposure of DU145 cells to 17 induced cellular senescence confirmed by senescence marker β-galactosidase staining of cells on post exposure to 17. The results from this current report support that the oxazolidinone derivatives with ethyl and acryl substitutions showed promising anticancer activity which will be helpful to develop further novel anticancer agents with better therapeutic potential.
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Andreeva OV, Babaev VM, Rizvanov IK, Strobykina IY, Kataev VE. Macrocyclic derivatives of isosteviol with two tetracyclic diterpenoid skeletons. RUSS J GEN CHEM+ 2014. [DOI: 10.1134/s1070363214020261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Malki A, Laha R, Bergmeier SC. Synthesis and cytotoxic activity of MOM-ether analogs of isosteviol. Bioorg Med Chem Lett 2014; 24:1184-7. [DOI: 10.1016/j.bmcl.2013.12.103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/22/2013] [Accepted: 12/24/2013] [Indexed: 10/25/2022]
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Lohoelter C, Brutschy M, Lubczyk D, Waldvogel SR. Novel supramolecular affinity materials based on (-)-isosteviol as molecular templates. Beilstein J Org Chem 2013; 9:2821-33. [PMID: 24367446 PMCID: PMC3869372 DOI: 10.3762/bjoc.9.317] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/07/2013] [Indexed: 01/20/2023] Open
Abstract
The readily available ex-chiral-pool building block (-)-isosteviol was combined with the C 3-symmetric platforms hexahydroxytriphenylene and hexaaminotriptycene providing large and rigid molecular architectures. Because of the persistent cavities these scaffolds are very potent supramolecular affinity materials for head space analysis by quartz crystal microbalances. The scaffolds serve in particular as templates for tracing air-borne arenes at low concentration. The affinities of the synthesized materials towards different air-borne arenes were determined by 200 MHz quartz crystal microbalances.
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Affiliation(s)
- Christina Lohoelter
- Institute for Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany
| | - Malte Brutschy
- Institute for Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany
| | - Daniel Lubczyk
- Institute for Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany
| | - Siegfried R Waldvogel
- Institute for Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany
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Lohoelter C, Weckbecker M, Waldvogel SR. (-)-Isosteviol as a Versatile Ex-Chiral-Pool Building Block for Organic Chemistry. European J Org Chem 2013. [DOI: 10.1002/ejoc.201300447] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ukiya M, Sawada S, Kikuchi T, Kushi Y, Fukatsu M, Akihisa T. Cytotoxic and Apoptosis-Inducing Activities of Steviol and Isosteviol Derivatives against Human Cancer Cell Lines. Chem Biodivers 2013; 10:177-88. [DOI: 10.1002/cbdv.201200406] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Indexed: 11/07/2022]
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Moons N, Goyens D, Jacobs J, Meervelt LV, De Borggraeve WM, Dehaen W. Fused derivatives of (iso)steviol via pericyclic reactions. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Khaybullin RN, Strobykina IY, Dobrynin AB, Gubaydullin AT, Chestnova RV, Babaev VM, Kataev VE. Synthesis and antituberculosis activity of novel unfolded and macrocyclic derivatives of ent-kaurane steviol. Bioorg Med Chem Lett 2012; 22:6909-13. [DOI: 10.1016/j.bmcl.2012.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/04/2012] [Accepted: 09/06/2012] [Indexed: 10/27/2022]
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Lohoelter C, Schollmeyer D, Waldvogel SR. Derivatives of (-)-Isosteviol with Expanded Ring D and Various Oxygen Functionalities. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200970] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ma ZW, Liu YX, Huo LJ, Gao X, Tao JC. Doubly stereocontrolled asymmetric Michael addition of acetylacetone to nitroolefins promoted by an isosteviol-derived bifunctional thiourea. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.tetasy.2012.03.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Ma ZW, Liu YX, Li PL, Ren H, Zhu Y, Tao JC. A highly efficient large-scale asymmetric Michael addition of isobutyraldehyde to maleimides promoted by a novel multifunctional thiourea. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.tetasy.2011.10.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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