Synthesis of 2-Arylquinazolin-4(3H)-ones by N-Aryl Benzamidines with Aromatic Carbonates

The reaction of N-aryl benzamidines 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n with diphenyl carbonate 2a or ethyl phenyl carbonate 2b synthesized 2-arylquinazolin-4(3H)-ones 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n in simple and safe process with good yields (71-90%). It was suggested that different electron-donating substituent in N-aryl benzamidines 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n afforded similar effect to the yields of 2-arylquinazolin-4(3H)-ones 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n. In these reactions, N-aryl benzamidines 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n built up intermediate compounds by nucleophilic addition to carbonates 2 to give annulation products 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n, following to cyclization involving the elimination of ethanol/phenol.