Microwave-Assisted Regioselective Synthesis of Variously Functionalized [1,2,4]triazolo[3,4-b]quinazolin-5(1H)-ones

[1,2,4]Triazolo[3,4-b]quinazolin-5(1H)-ones with varied functionalization patterns were synthesized in a regioselective manner by reacting 2-thioxo-2,3- dihydroquinazolin-4(1H)-one (2) with variously functionalized hydrazonoyl chlorides (3ah). Linear regioselectivity of the formed products was confirmed by X-ray measurements. Under microwave conditions, the reactions were completed in a few minutes without a change in the regioselectivity.