| abstract |
PROBLEM TO BE SOLVED: To provide a compound having steroid C 17,20 lyase inhibitory activity and useful as a prophylactic or therapeutic agent for tumors such as prostatic disease and breast cancer, and a method for efficiently separating an optically active form of the compound from an optical isomer mixture Offer. SOLUTION: [Chemical 1] [Wherein each symbol is as defined in the specification] or a salt thereof or a prodrug thereof, and a mixture of optical isomers are optically resolved using a resolving agent such as tartranic acid. A method for obtaining an optically active substance. [Selection figure] None |