Journal ArticleDOI
Lignans from Machilus edulis
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TLDR
Physical properties including NMR and MS data as well as chemical degradation reactions are reported for the first time for these lignans.About:
This article is published in Phytochemistry.The article was published on 1972-02-01. It has received 16 citations till now. The article focuses on the topics: Machilus & Lignan.read more
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Chemical constituents of the bark of Machilus wangchiana and their biological activities.
Wei Cheng,Cheng-Gen Zhu,Wendong Xu,Xiaona Fan,Yongchun Yang,Yan Li,Xiaoguang Chen,Wen-Jie Wang,Jiangong Shi +8 more
TL;DR: Eleven new metabolites, butanolides 1-6, lignan derivatives 7-9, sesquiterpene 10, and 3',4'-seco-flavane derivative 11, have been isolated from an ethanol extract of Machilus wangchiana, and Isomahubannolide-23 was cytotoxic against human stomach cancer and ovarian cancer cell lines.
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Antifungal constituents from roots of Virola surinamensis
TL;DR: Chromatographic fractionation of the dichloromethane extract from roots of Virolasurinamensis yielded two new natural products, 3- epi -juruenolide C and 2′-hydroxy-7,4′-dimethoxyisoflavone, as well as various known steroids, lignans, isoflavones,flavonoids and diarylpropanes.
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Lipophyllic antioxidants from Iryanthera juruensis fruits.
Dulce Helena Siqueira Silva,Francisco Cezar Belchor Lages Pereira,Maria Valnice Boldrin Zanoni,Massayoshi Yoshida,Massayoshi Yoshida +4 more
TL;DR: The phytochemical investigation of the hexane extract of Iryanthera juruensis (Myristicaceae) fruits led to the isolation of two tocotrienols and four lignans which exhibited antioxidant activity towards beta-carotene on TLC autographic assay.
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Bioactive Neolignans and Lignans from the Bark of Machilus robusta
Yanru Li,Wei Cheng,Cheng-Gen Zhu,Chun-Suo Yao,Liang Xiong,Ye Tian,Sujuan Wang,Sheng Lin,Jin-Feng Hu,Yongchun Yang,Ying Guo,Ying Yang,Yan Li,Yu-He Yuan,Nai-Hong Chen,Jiangong Shi +15 more
TL;DR: Sixteen new neolignans and lignans (1-16), together with 12 known analogues, have been isolated from an ethanol extract of the bark of Machilus robusta, and the known compounds (-)-pinoresinol and (+)-lyoniresinol were active against serum deprivation induced PC12 cell damage.
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Enantioselective installation of adjacent tertiary benzylic stereocentres using lithiation–borylation–protodeboronation methodology. Application to the synthesis of bifluranol and fluorohexestrol
Abstract: 1,2-Diaryl ethanes bearing 1,2-stereogenic centres show interesting biological activity but their stereocontrolled synthesis has not been reported forcing a reliance of methods involving diastereomer and enantiomer separation. We have found that this class of molecules can be prepared with very high stereocontrol using lithiation–borylation methodology. The reaction of an enantioenriched benzylic lithiated carbamate with an enantioenriched benzylic secondary pinacol boronic ester gave a tertiary boronic ester with complete diastereo- and enantiocontrol. It was essential to use MgBr2/MeOH after formation of the boronate complex, both to promote the 1,2-migration and to trap any lithiated carbamate/benzylic anion that formed from fragmentation of the ate complex, anions that would otherwise racemise and re-form the boronate complex eroding both er and dr of the product. When the benzylic lithiated carbamate and benzylic secondary pinacol boronic ester were too hindered, boronate complex did not even form. In these cases, it was found that the use of the less hindered neopentyl boronic esters enabled successful homologation to take place even for the most hindered reaction partners, with high stereocontrol and without the need for additives. Protodeboronation of the product boronic esters with TBAF gave the target 1,2-diaryl ethanes bearing 1,2-stereogenic centres. The methodology was applied to the stereocontrolled synthesis of bifluranol and fluorohexestrol in just 7 and 5 steps, respectively.
References
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The Biological Effects and the Chemical Composition of Podophyllin. A Review
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The chemical constituents of Himantandra species. I. The Lignins of Himantandra baccata Bail. and H. belgraveana F. Muell
GK Hughes,E Ritchie +1 more
TL;DR: Three new lignans have been isolated from Himantandra baccata Bail and one from H. belgraveana F. Muell as mentioned in this paper, two are phenyltetralins and the other two are αα?-disubstituted tetrahydrofurans.
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Application of Tosylate Reductions and Molecular Rotations to the Stereochemistry of Lignans2
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