A Facile and Regioselective Synthesis of 2‐Formamidothiazoles via the C−H Formamidation of Thiazole N‐oxides with Isocyanides

Abstract A facile, microwave‐promoted, regioselective C−H formamidation of thiazole N ‐oxides with isocyanides in the presence of TBDPSCl was developed. Various 2‐( N ‐substituted formamido)thiazoles were obtained in moderate to high yields. In the case of the C2‐substituted thiazole N ‐oxides, the C−H formamidation took place selectively at the C4 position of the thiazole ring. This transformation is also applicable to some other N ‐containing heterocyclic derivatives such as pyridine, quinoline, and pyridazine N ‐oxides and has advantages such as broad substrate tolerance, high regioselectivity, and mild reaction conditions.