A fast and facile one-pot procedure for the preparation of symmetric 5-Aryloyl-1,9-dimethyl-5,9-dihydro-2H-pyrano[2,3-d:6,5-d']dipyrimidine-2,4,6,8(1H,3H,7H)-tetraone derivatives by two-component reaction of N-methylbarbituric acid and arylglyoxalmonohydrates catalyzed by DABCO in ethanol at 50 ºC is described. This protocol has the advantages of environmental friendless, very simple operation, high regio- and chemoselectivity and moderate to excellent yields.
The title compound 3-amino-5-(4-chlorophenyl)pyridazine-4-carbonitrile was prepared by a one-pot three-component reaction of malononitrile with corresponding arylglyoxal in the presence of hydrazine hydrate at room temperature in water and ethanol. Its structure was also con?rmed by its IR, 1H, 13C-NMR, Mass spectral data and elemental analysis. The compound was crystallized in the monoclinic system, space group P21/c, a = 3.817(3) ?, b = 13.533(10) ?, c = 19.607(15) ?, B = 93.401(10)°, Z=4, R1 = 0.0906 and wR2 = 0.1422. The crystal structure of the compound also shows a weak intermolecular interaction between N1 atom of one molecule and N3 atom of the other molecule.