Visible light-induced cascade N -alkylation/amidation reaction of quinazolin-4(3 H )-ones and related N-heterocycles.

An efficient and visible light-promoted cascade N -alkylation/amidation of quinazolin-4(3 H )-ones with benzyl halides and allyl halides has been described for the first time to provide a convenient access to quinazoline-2,4(1 H ,3 H )-diones. This cascade N -alkylation/amidation reaction shows good functional group tolerance and could also be applied to N-heterocycles such as benzo[ d ]thiazoles, benzo[ d ]imidazoles, and quinazolines. Control experiments show that K 2 CO 3 plays an important role in this transformation.