A new and facile synthesis of N-benzyl-N′-acylureas via reaction of dibenzoylhydrazine carboxamide and benzylamines

Abstract

Herein, we report a new method of synthesis of N-acylureas (E1-5) via reaction of dibenzoylhydrazine carboxamide (N,2-bis(4-methoxybenzoyl)hydrazine-1-carboxamide) (C) and various benzylamines. Preparation of dibenzoylhydrazine carboxamide was performed by the treatment of 5,6-diaryl-3-methylthio-1,2,4-triazine (B) with Oxone which leads to oxidation and triazine ring cleavage in high yield (82%). Five benzylamine derivatives containing different electron donating and withdrawing substituents were used in this study. Yields for the conversion of dibenzoylhydrazine carboxamide (C) to N-acylureas (E1-5) were in the range of 40-55%. The structures of the intermediates and final products were characterized and confirmed by NMR, mass spectrometry and single-crystal X-ray crystallography.