A practical synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid—the key precursor toward imatinib

Abstract

A simple and efficient in situ synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid through direct reductive alkylation of 1-methylpiperazine in the presence of triacetoxy sodium borohydride in 95–99% yields is elaborated. The process is easy to scale-up for the large-scale synthesis of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid as the key synthetic intermediate of imatinib. This method was used for the synthesis of benzyl derivatives of heterocyclic amines in 87–90% yields.