Dehydration of Amides to Nitriles Initiated by Hexamethylphosphoric Triamide

Abstract

Aliphatic and aromatic carboxamides are found to undergo ready dehydration in hexamethylphosphoric triamide at 220-240" affording the corresponding nitriles in good yield.Les carboxamides aliphatiques et aromatiques subissent une dkshydratation facile dans le HMPT a 220-240" et conduisent aux nitriles correspondants avec un bon rendement.

Recent developments in dehydration of primary amides to nitriles

“…Monson and Priest reported the dehydration of aliphatic and aromatic carboxamides to their corresponding nitriles in hexamethylphosphoric triamide (HMPT) at 220-240°C in good yields viz., propionamide (94%), n-butyramide (75%), hexanamide (78%), banzamide (67%), phenylacetamide (75%) and adipamide (49%) (Scheme 10). 44 The plausible mechanism for this reaction involves the evolution of dimethylamine, the formation of a phosphorodiamidate derivative of the amide, and the elimination of the phosphorodiamidate leaving group to form the nitrile (Scheme 10).…”