Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO3)2 or imidazole as catalysts.

A Rosie Chhatwal,Helen V Lomax,A John Blacker,Patricia Marcé,Jonathan M J Williams

doi:10.1039/d0sc01317j

Abstract

A new method for the direct synthesis of primary and secondary amides from carboxylic acids is described using Mg(NO3)2·6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source. This methodology is particularly useful for the direct synthesis of primary and methyl amides avoiding the use of ammonia and methylamine gas which can be tedious to manipulate. Furthermore, the transformation does not require the employment of coupling or activating agents which are commonly required.

Highlights

A new method for the direct synthesis of primary and secondary amides from carboxylic acids is described using Mg(NO3)2$6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source. This methodology is useful for the direct synthesis of primary and methyl amides avoiding the use of ammonia and methylamine gas which can be tedious to manipulate
The importance of the amide functional group emerges from their presence in many crucial compounds such as proteins, fabrics, fertilizers, insecticides, plastics, drugs, and in a vast number of synthetic structures
We present a new protocol for the synthesis of amides from nonactivated carboxylic acids by direct coupling using a lowcost, readily available, and easy to manipulate catalyst and nitrogen source

Summary

Introduction

The importance of the amide functional group emerges from their presence in many crucial compounds such as proteins, fabrics, fertilizers, insecticides, plastics, drugs, and in a vast number of synthetic structures. Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO3)[2] or imidazole as catalysts†‡ A new method for the direct synthesis of primary and secondary amides from carboxylic acids is described using Mg(NO3)2$6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source.

Results

Conclusion