One-Pot Synthesis of Salicylanilides by Direct Amide Bond Formation from Salicyclic Acid Under Microwave Irradiation

Abstract

A highly efficient protocol for the preparation of aromatic amides is described by the direct reactions between salicyclic acid and aromatic amines in the presence of phosphorous trichloride under microwave irradiation. The method has several advantages over the conventional methods, including operational simplicity, good yield, and reduced reaction time.

Keywords:

• Microwave irradiation
• salicylanilide
• synthesis

ACKNOWLEDGMENT

We are grateful to the Junzheng Scholar Project of Soochow University for financial support.

Notes

^a In isolated products. Conditions: 40 mol% PCl₃, in xylene, 300 W.

^b By conventional heating (using an oil bath).

^a In isolated products. Conditions: 33 min in xylene, 300 W.

^a In isolated products. Conditions: 40 mol% PCl₃, in xylene, 300 W.

^b The time required for the disappearance of salicyclic acid on TLC.

^c Isolated yields by recrystallization except entries a, e, and j.

^d By conventional heating (using an oil bath).