An ultrasound-promoted green approach for the N-formylation of amines under solvent- and catalyst-free conditions at room temperature

Research highlights:•The ultrasonic irradiation accelerates the N-formylation of amines by formic acid.•The reaction will take place under solvent- and catalyst-free conditions.•The reaction will take place at room temperature.•Better reaction times, higher yields and easier work-up.•Recovery of the excess of formic acid.•No side product was observed under the reaction conditions.•The separation techniques are not required to obtain the pure compounds.

A new environmentally benign, convenient, and facile methodology for the N-formylation of amines is reported using ultrasound irradiation under solvent- and catalyst-free conditions at room temperature. Compared with conventional methods, the main advantages of the present procedure are milder, cleaner and greener conditions, shorter reaction time, higher purity and yields, simpler work-up, and lower generation of waste or pollutions.

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