| abstract |
Compounds of the formula: wherein R1 is hydrogen or carboxy protective group, R2, R5, R6 and R7 are each hydrogen or hydroxy, R3 and R4 are each hydrogen, or combined to form epoxy or single bond, R8 and R9 are each optionally substituted aryl, and X is single bond or methylene, in addition to the above, R2 and R3 may be combined to form single bond; provided that when R2, R5, R6 and R7 are each hydrogen, then R3 and R4 are combined to form epoxy; when R3 and R4 are combined to form single bond, then at least one of R2, R5, R6 and R7 is hydroxy and the other(s) is (are) hydrogen; and when R3 and R4 are each hydrogen, then at least one of R2, R5, R6 and R7 is hydroxy and the other(s) is (are) hydrogen, and X is methylene, or its salt, process for preparing it, a pharmaceutical composition including it, and a use thereof. |