| abstract |
The present invention relates to a process for preparing a pharmaceutical starting compound compound by hydrolyzing a compound of the general formula (II): Wherein R1 is protected carboxy, R2 is lower alkoxy or higher alkoxy, A1 is an aromatic bivalent group, hererocyclic bivalent group or cyclo (lower) alkane bivalent group, and A2 is an aromatic bivalent group, heterocyclic bivalent group or cyclo (lower) alkane bivalent group, with aqueous potassium hydroxide and by treating with hydrochloric acid. |