A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).

An effective method for the synthesis of quinolino[2,1-b]quinazolinones was described. The O-directing Rh(III)-catalyzed C-H activation of 3-arylquinazolinones and alkynes gave the corresponding polyaryl substituted quinolino[2,1-b]quinazolinones in good to excellent yields....

An efficient synthesis route of indazole fused dihydrophenanthridinones with excellent to almost quantitative yields under mild reaction conditions was developed by acid-controlled Rh(III)-catalyzed C-H activation of 3-arylindazoles and annulation with...