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 (C) 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.

Graphical Abstract

Keywords:

• Carbamoylbenzamide
• N-benzyl-N′-acylurea
• Ureide
• X-ray crystallography

Disclosure statement

No potential conflict of interest was reported by the author(s).

Acknowledgments

We thank the University of Reading for access to the Chemical Analysis Facility (CAF) and Mr. Nick Spencer for help with X-ray data collection.

Additional information

Funding

This work was supported by a grant [Grant no. 91-53] from Research Council of Mazandaran University of Medical Sciences, Sari, Iran.