Role of Water in the Photochemical Synthesis of Methyl 12-Oxo-6,12-dihydroazepino[2,1-b]quinazoline-8-carboxylates

Methyl 12-oxo-6,12-dihydroazepino[2,1-b]quinazoline-8-carboxylate and methyl 3H-azepin-2(1H)-one-5-carboxylate were synthesized by photoinduced heterocyclization of methyl 4-azidobenzoate and ethyl 2-aminobenzoate in the THF–water and acetonitrile­–water mixtures. It was found that the yields of methyl 12-oxo-6,12-dihydroazepino[2,1-b]quinazolate increase with rising water content in the reaction mixture.