Study on Synthesis of anti-brassinosteroids

油菜素类固醇(BRs)是近年来被公认的重要的类固醇植物激素。然而，它在植物生长中的基本功能还没有被阐明。本研究旨在合成可作为研究BRS功能的工具的BR拮抗剂。我们尝试合成了以下两个化合物1。引入甲基的化合物的合成。通过八步反应将豆甾醇转化为6，6-亚乙二氧基豆甾酮-22-烯-3-酮。后者与碘甲烷在二异丙胺锂存在下反应，得到2α-单甲基、2，2-二甲基、2α-4α-二甲基衍生物。我们现在正尝试使用已知的反应序列在这些化合物中引入22R，23R-羟基。环上含有硫杂环己烷的化合物的合成通过5个反应将豆甾醇转化为22S，23S-二羟基-2-烯-6-酮。我们现在正试图在环中引入硫杂环己烷。

Brassinosteroids (BRs) are steroidal plant hormones of which importance has been recognized for these years. However, its basic function in plant growth has not yet been clarified. This research aims at the synthesis of BR antagonists which could be used as a tool to investigate functions of BRS. We attempted to synthesis the following two compounds.1. Synthesis of compounds in which methyl groups are introduced. Stigmasterol was converted to 6,6-ethylenedioxystigmast-22-en-3- one using eight steps of reactions. The latter is reacted with methyl iodide under the presence of lithium diisopropylamide to give 2alpha-monomethyl, 2,2-dimethyl, 2alpha 4alpha -dimethyl derivatives. We are now attempting to introduce 22R, 23R-hydroxyls in these compounds using known reaction sequences.2. Synthesis of a compound with thiirane in A ring. Stigmasterol was converted to 22S,23S-dihydroxystigmast-2-en-6-one using five reactions. We are now attempting to introduce thiirane in A ring.