Brønsted acid-promoted ring-opening and annulation of thioamides and 2H-azirines to synthesize 2,4,5-trisubstituted thiazoles

We have developed a metal-free synthesis method of 2,4,5-trisubstituted thiazoles by the formation of C–S and C–N bonds.It is a green and efficient way with a broad substrate scope. And this protocol features mild conditions and simple operation.