The reaction of 4‐oxo‐3,4‐dihydroquinazolinyl‐2‐guanidine 1 with several active methylene compounds
has revealed formation of the corresponding hydropyrimidine and dihydropyrimidnone (DHPMs) derivatives
via cycloaddition reaction mechanism. Satisfactory results were obtained with good yields, short time,
and simplicity in the experimental procedure. Reaction with ketones in DMF proceeded via (5+1)
heterocyclization and resulted in the formation of 2‐amino‐4‐(het)aryl‐4,6‐dihydro‐1(3)(11)H‐[1,3,5]
triazino[2,1‐b]quinazolin‐6‐ones 8‐13, respectively. All compounds have been characterized based on IR,
1H‐NMR, and mass spectrum.