Piperazine derivatives of benzimidazole as potential anthelmintics. Part 1: Synthesis and activity of methyl-5-(4-substituted piperazin-1-yl)benzimidazole-2-carbamates.

A series of 5-(4-substituted piperazin-1-yl)-2-nitroanilines (4) and 5-(4-substituted piperazin-1-yl)benzimidazole-2-carbamates (6) has been synthesized starting from 5-chloro-2-nitroaniline (3) and N-monosubstituted piperazines. Catalytic reduction of 4 with Pd/C followed by treatment with 1,3-dicarbomethoxy-S-methylisothiourea yielded the corresponding methyl-5-(4-substituted piperazin-1-yl)benzimidazole-2-carbamates (6) which were for anthelmintic activity against experimental infections of Trichinella spiralis.