Synthesis of new Δ5-7-oxygenated and Δ5,7-unsaturated brassinosteroid analogs
作者:Bernhard Hellrung、Brunhilde Voigt、Jürgen Schmidt、Günter Adam
DOI:10.1016/s0039-128x(97)00008-1
日期:1997.5
We report on the synthesis of the brassinosteroid analogs (22R,23R)-3 beta,7 beta,22,23-tetrahydroxy-stigmast-5-ene (13), (22R,23R)-3 beta,7 alpha,22,23-tetrahydroxy-stigmast-5-ene (15), and (22R,23R)-3 beta-22,23-trihydroxy-stigmast- 5,7-diene (18) by means of the osmium-catalyzed asymmetric dihydroxylation of intermediate 1, available from stigmasterol. This reaction sequence produced the expected (22S,23S)- and (22R,23R)-triols 6 and 7 as well as the 22,23-diketo derivatives 2 and 3. The phytohormone activity of the new brassinosteroid analogs is discussed. (C) 1997 by Elsevier Science Inc.
Synthesis and cytotoxicity evaluation of 22,23-oxygenated stigmastane derivatives
作者:Alexander Yu. Misharin、Arif R. Mehtiev、Galina E. Morozevich、Yaroslav V. Tkachev、Vladimir P. Timofeev
DOI:10.1016/j.bmc.2007.10.056
日期:2008.2.1
Starting from (22E)-3 alpha,5 alpha-cyclo-6 beta-methoxystigmast-22-ene eighteen derivatives of (22S,23S)-22,23-oxidostigmastane, (22R,23R)-22,23-oxidostigmastane, and (22R,23R)-22,23-dihydroxystigmastane were synthesized and screened for cytotoxicity in human hepatoma Hep G2 cells and human breast carcinoma MCF-7 cells using MTT assay. Four compounds of this series exhibited high cytotoxicity in both cells; three compounds were selectively toxic in MCF-7 cells, one compound was toxic in Hep G2 cells, rather than in MCF-7 cells; four compounds at low concentrations increased MTT test values over the control. (C) 2007 Elsevier Ltd. All rights reserved.