Synthesis of N-Boc-Protected Bis(2-benzimidazolylmethyl)amines

Abstract

Preparation of bis(1-tert-butoxycarbonyl-2-benzimidazolylmethyl)amines from N-tert-butoxycarbonyl-protected 2-chloromethylbenzimidazole is described. The reaction with primary amines containing several functional groups afforded bis(1-tertbutoxycarbonyl-2-benzimidazolylmethyl)amines in good yields. Hydrogenolysis of bis(2-benzimidazolylmethyl)benzylamine, catalyzed by Pd(OH) 2 /C, cleaved the benzyl group, leaving the tertbutoxycarbonyl and 2-benzimidazolylmethyl groups intact. The product of the latter reaction, bis(1-tert-butoxycarbonyl-2-benzimidazolylmethyl)amine, was thus obtained in 56% yield; the presence of the tert-butoxycarbonyl groups at the N-benzimidazole positions makes it amenable to further functionalization at the central nitrogen atom.