| 摘要 |
PURPOSE: To obtain an optically active compound little in byproducts, useful for obtaining the raw material of a quinolone derivative in a high optical purity under a mild condition by treating a specific azaspiro derivative with the cells, culture solution, etc., of a specific microorganism. CONSTITUTION: (A) A compound of formula I (R is benzyl, trityl, benzhydryl, lower alkyl, wherein when the group has a benzene ring or benzene rings, the benzene ring or benzene rings may have a substituent; n is 2,3) is treated with (B) the cells, culture solution or cell-treated product of a microorganism belonging to the genus Phaeocreopsis sp. and having an asymmetrically reducing ability to obtain the objective compound of formula II. The objective compound of formula II is obtained e.g. by suspending the component A in a buffer solution, adding the component B to the suspension, treating the mixture at a pH of 4-9 at 5-60 deg.C for 1-3 days with stirring, filtering off the cells from the treated solution, extracting the filtrate, and subsequently subjecting the extract to operations such as a vacuum-concentration treatment. |
