This manuscript is dedicated to the late Prof. Alan R. Katritzky for his notable contributions to benzotriazole chemistry.
Abstract
A diverse range of ureas, N -acylureas, carbamates, and thiocarbamates has been synthesized in good to excellent yields by reacting N -acylbenzotriazoles individually with amines or amides or phenols or thiols in the presence of diphenylphosphoryl azide (DPPA) as a suitable azide donor in anhydrous toluene at 110 °C for 3–4 hours. In this route, DPPA was found to be a good alternative to trimethylsilyl azide and sodium azide for the azide donor in Curtius degradation. The high reaction yields, one-pot and metal-free conditions, straightforward nature, easy handling, use of readily available reagents, and in many cases avoidance of column chromatography are the notable features of the devised protocol.
Key words
N -acylbenzotriazoles -
N -acylureas - benzotriazoles - Curtius rearrangement - diphenylphosphoryl azide - carbamates - thiocarbamates - ureas