A simple and efficient method for preparation of 2-amino-3substituted quinazolin-4(3H)-ones by reaction of cyanuric chloride with 2-amino N-substituted benzamides in acetonitrile-water (2 : 1) using sodium bicarbonate as a mild base is described. Using this metal-free method, a variety of 2amino-3-substituted quinazolin-4(3H)-ones were obtained in good to excellent yields. Here, both organic and inorganic bases were found to promote this reaction and the best results were observed with sodium bicarbonate. This study is the first observation of cyanuric chloride to act as a source for creation of amine functionality in 2-amino-3-substituted quinazolin-4(3H)-ones.

Hydrazonoyl chlorides underwent unprecedented stereoselective [3 + 2] cycloaddition reaction with β-oxodithioesters and β-oxothioamides under Lewis acid catalysis producing (Z)-1,3,4-thiadiazol-2(3H)-ylidenes in high yields. These products are obtained also with a base. Though same products are obtained in both these conditions, they involve different reaction mechanisms. In base mediated reactions, 1,3-dipolar cycloaddition of a nitrilimine to C=S is operative and in Lewis acid catalysed reactions, β-oxodithioester/β-oxothioamide undergoes addition-cyclization reactions with a hydrazonoyl chloride.

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