DMSO as C1 Source under Metal‐ and Oxidant‐free Conditions: NH4SCN‐mediated Synthesis of Quinazolinone and Dihydroquinazolin‐4(1H)‐one Derivatives

Abstract A new and efficient strategy for the development of quinazolinones and dihydroquinazolin‐4(1H)‐ones promoted by ammonium thiocyanate is reported. Most remarkably, dimethyl sulfoxide is used for solvent as well as methine and bridged methylene source to obtain a wide variety of new N, N ‐disubstituted 2,3‐ dihydroquinazolin‐4(1H)‐ones. This transformation possesses significant advantages such as metal‐ and oxidant‐free, non‐acidic medium, simple condition, good functional group tolerance and broad substrate scope. Besides, this process could be readily scaled up and applied to drug molecules synthesis.