Study on Synthesis of anti-brassinosteroids

类甾醇（BR）是甾体植物激素，其重要性近年来已被认识到。然而，其在植物生长中的基本功能尚未阐明。本研究旨在合成BR拮抗剂，为研究BRS的功能奠定基础。我们尝试合成以下两种化合物。其中引入甲基的化合物的合成。豆甾醇通过8步反应转化为6，6-亚乙基二氧豆甾-22-烯-3-酮。后者在二异丙基氨基锂存在下与碘甲烷反应，得到2 α-单甲基，2，2-二甲基，2 α-4 α-二甲基衍生物。我们现在正尝试使用已知的反应顺序在这些化合物中引入22 R，23 R-羟基。A环含硫杂环丙烷化合物的合成。豆甾醇通过5个反应转化为22 S，23 S-二羟基豆甾-2-烯-6-酮。我们现在正试图在A环中引入硫杂环丙烷。

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.