Rhodium-Catalyzed C-H Activation of 2-Arylquinazolinones and Cyclization with Elemental Sulfur Via C-S/S-N Bond Formation to a Ccess 7h-Benzo[4,5]Isothiazolo[3,2-B]Quinazolinones

An efficient method for the synthesis of 7H-benzo[4,5] isothiazolo[3,2-b]quinazolin-7-ones by the reaction of 2-arylquinazolin-4(3H)-ones and elemental sulfur is described. The rhodium-catalyzed C-H activation of 2-arylquinazolinones and cyclization with elemental sulfur via one-step formation of C-S/N-S bonds to give the corresponding 7H-benzo[4,5] isothiazolo[3,2-b]quinazolinones is realized in good to high yields with good functional group tolerance.