NOVEL PROCESSES AND INTERMEDIATES FOR THE PREPARATION OF PIPERAZINE DERIVATIVES

摘要

Compounds having the formula R?5O-A-NR4-R2¿ (V), where R2 is a heteroaryl group linked to the remainder of the molecule via a carbon atom adjacent a nitrogen atom and R?4 and R5¿ are both hydrogen atoms or together represent -SO- or -SO¿2?- and A is C2-C4 alkylene optionally substituted by one or more lower alkyl groups are novel intermediates in the preparation of pharmaceutically useful piperazine derivatives as end compounds. The compounds having formula (V) where R?4 and R5¿ are hydrogen may be prepared by a rearrangement of a compound having the formula R2-O-A-NH¿2? (VI).