摘要:
The present invention relates to a process for the preparation of a compound of the following formula (I)
wherein one of R₁ and R₂ is hydrogen or halogen and the other is independently, an amino group or a C₂-C₄ alkanoyl amino group; R₃ is hydrogen; a linear or branched alkyl, C₁-C₄ alkoxy or C₂-C₄ alkoxycarbonyl group; halogen; or phenyl unsubstituted or substituted by a C₁-C₄ alkyl group; A is a group -(CH₂) n -Het wherein Het is an optionally substituted heteromonocyclic or heterobicyclic ring containing one or two nitrogen atoms and n is zero or an integer of 1 to 3; and the symbol .... ¯ represents a single or double bond and the pharmaceutically acceptable salts thereof. The compounds of the invention can be useful as 5HT3 receptor antagonists.