Visible-light-mediated reaction: synthesis of quinazolinones from 1,2-dihydroquinazoline 3-oxides

Abstract

1-Methyl-2-phenylquinazolin-4(1H)-ones were synthesized in good yield by exposing 1,4-dimethyl-2-phenyl-1,2-dihydroquinazoline 3-oxides or 1-methyl-2-phenyl-1,2-dihydroquinazoline 3-oxides to visible light in acetonitrile in the absence of any external photosensitizers. The key intermediate for this photochemical reaction was isolated and identified as 1-methyl-2-phenyl-1,4-dihydroquinazolin-4-ol. The mechanism of this photosensitizer-free, visible-light-mediated reaction was proposed.