| 摘要 |
PURPOSE:To obtain the titled compound useful as a preparation intermediate of a beta-lactam antibiotic, in high yield and stereoselectivity, by using a specific 2-azetidinone derivative as a starting material, and nitrosating and reducing the material. CONSTITUTION:The compound of formula I (R<1> and R<2> are independently protecting groups, or together form a protecting group) obtained by introducing a protecting group to (4R)-4-(2-hydroxyethyl)-2-azetidinone, is treated with a strong base in an inert organic solvent at -100--20 deg.C, and the product is made to react with a nitrosation agent such as isoamyl nitrite, ethyl nitrite, etc. at -100-+50 deg.C to obtain the novel optically active hydroxyimino compound of formula II. The obtained compound of formula II is converted to the optically active 2-azetidinone derivative of formula III by contacting with hydrogen at 10-50 deg.C and 1-5atm in the presence of a catalyst (preferably a noble metal catalyst). |
