Quinazolin-4( 3H )-ones derivatives represent an important class of nitrogen-containing heterocycles with diverse biological and pharmacological activities, and their significance makes their efficient synthesis highly desirable. In this context, we report here a simple, efficient and green one-pot synthetic protocol for the preparation of 2-substituted quinazolin-4( 3H )-ones via cyclocondensation of 2-aminobenzamide with variety aldehydes, employing scandium triflate Sc(OTf) 3 as a water-tolerant and recyclable Lewis acid catalyst. The reactions were carried out at room temperature in dichloromethane, proceeding smoothly without the need for any external oxidant. The transformation involves in situ imine formation followed by intramolecular cyclization and aerobic oxidation. A broad range of aldehydes, including aromatic and heteroaromatic substrates bearing both electron-donating and electron-withdrawing groups, were well tolerated affording the desired products in good to excellent yields (70–90%) within short reaction times (3–5 hours). This green methodology offers several significant advantages, such as mild reaction condition, operational simplicity, high selectivity and reduced environmental impact. A key feature of this methodology lies in the facile recovery of Sc(OTf) 3 catalyst through simple aqueous extraction and its recyclability over multiple cycles without significant defeat of efficiency, underscoring its potential in sustainable organic synthesis.
Gorepatil et al. (Thu,) studied this question.