Study on Synthesis of anti-brassinosteroids

油菜素内酯（BRs）是一种甾体植物激素，其重要性近年来已被认识到。但其在植物生长中的基本功能尚不清楚。本研究旨在合成BR拮抗剂，作为研究BR功能的工具。我们试图合成以下两种化合物。引入甲基的化合物的合成。通过8步反应将豆甾醇转化为6,6-乙二氧豆甾醇-22-烯-3- 1。后者在二异丙酰胺锂存在下与碘化甲酯反应得到2 α -单甲基、2,2-二甲基、2 α - 4 α -二甲基衍生物。我们现在正尝试用已知的反应序列在这些化合物中引入22R、23r -羟基。a环含硫代烷化合物的合成。通过5个反应将豆甾醇转化为22S， 23s -二羟基豆甾醇-2-烯-6- 1。我们现在尝试在A环中引入硫代烷。

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.