| 摘要 |
NEW MATERIAL:A compound of formula I [formula II is formula III (R' is 1-3C alkyl); Z is H, formula IV (R1-R3 are lower alkyl, phenyl)]. EXAMPLE:6beta-Methoy-24-trimethylsilyl-3alpha,5-cyclo-5alpha-chole-16- en-e-23-ine. USE:A synthetic intermediate of vitamin D or placinolide steroids as a plant growth regulator. It can be prepared in high yield without formation of isomers. PREPARATION:A compound of formula V as a feedstock is etherified with a compound of formula VI [X is halogen, R4SO2O (R4 is alkyl, phenyl which may be substituted). Then, the H atom in the acetylene group of the product is drawn off with a strong base and silylated with a compound of formula VII (Y is halogen). Further, the side methylene of the product of formula VIII is anionized with a strong base, then, subjected to [2,3]Wittig's rearrangement and the reaction product is treated with an acid.
|
