Visible-light photocatalyzed C-N bond activation of tertiary amines: a three-component approach to synthesize quinazolines.

A metal-free three-component approach has been developed to prepare 2,4-disubstituted quinazolines from o -acylanilines, trialkylamines and ammonium chloride under visible-light using eosin Y as the photocatalyst. The notable features of this work include (i) the use of tertiary amines as an alkyl synthon and triethanolamine as a C 2 -OH synthon; (ii) good functional group tolerance with 52%-98% yields; (iii) proof of concept with o -amino benzaldehyde as a substrate to deliver 2-methyl quinazoline 3pa; and (iv) gram-scale synthesis of compounds 3ga, 3ja and 3ma. A reductive quenching mechanism was proposed based on the control studies and redox potential values.