Iodoacetic Acid is an Efficient Reagent for the Synthesis of Amino Acid Derived 2-Aminobenzimidazoles

Abstract

Chiral, nonracemic, N-unprotected amino acids were converted into the corresponding N-benzimidazol-2-yl derivatives by a sequential procedure involving initial formation of isothiocyanates, their reaction with arene-1,2-diamines, and cyclization–desulfurization­ of the intermediate thioureas with iodoacetic acid. The simplified workup and the lack of volatile or toxic byproducts in the key desulfurization step renders iodoacetic acid a superior reagent to the usual reagent, iodomethane.

Key words

amino acids - cyclization - desulfurization - green chemistry - heterocycles

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