NOVEL PROCESSES AND INTERMEDIATES FOR THE PREPARATION OF PIPERAZINE DERIVATIVES

摘要

Compounds having the formula R<5>O-A-NR<4>-R<2> (V), where R<2> is a heteroaryl group linked to the remainder of the molecule via a carbon atom adjacent a nitrogen atom and R<4> and R<5> are both hydrogen atoms or together represent -SO- or -SO2- 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 R<5> are hydrogen may be prepared by a rearrangement of a compound having the formula R<2>-O-A-NH2 (VI).