L-Proline/K2CO3-Catalyzed Eco-friendly Synthesis of Novel 2-(1H-Indol-3-yl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one Derivatives

A green and eco-friendly synthesis of novel 2-(1 H -indol-3-yl)-3-phenyl-2,3-dihydroquinazolin-4(1 H )-one derivatives have been developed using L-proline as a simple catalyst. Two efficient methods have been described for the synthesis of dihydroquinazolin-4(1 H )-one derivatives. In the first method, 1 H -1,3-benz­oxazine-2,4-dione reacted with substituted anilines and 1 H -indole-3-carbaldehydes in water in the presence of L-proline as a catalyst, whereas in the second method, a similar reaction using 1 H -indol-3-ylmethanol instead of indole-3-carbaldehyde was catalyzed by L-proline/K 2 CO 3 at room temperature for 30 min to afford the same products. These two protocols involve eco-friendly and inexpensive catalysts and produce the target products in excellent yields with a sufficient purity, so that there was no need of column chromatography for their isolation or purification.