The novel ?-phosphorus labile ylide of 1-(p-tolyl)-2-(tri-p-tolylphosphoranylidene)ethanone (PTTPPY) is prepared by the reaction of 2-bromo-1-(p-tolyl)ethanone with tri-p-tolylphosphine in chloroform as solvent. The complexes of the type [HgX2(p-tolyl)3PCHCOC6H4CH3)] (X = Cl, Br and I) are prepared by the reaction of title ylide with mercury(II) halides in good yields, using methanol as solvent. The final products were characterized by IR, 1H, 13C, 31P NMR spectroscopic methods and microanalysis.

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.

A series of pyrido[2,3-b]pyrazine derivatives were synthesized in good to excellent yields by condensation reactions of arylglyoxals with 2,3-diaminopyridine in dimethylformamide and ethanol at 90 oC.

The title compound 3-(4-hydroxy-3-methoxyphenyl)-7,7-dimethyl-7,8-dihydrocinnolin-5(6H)-one (3) was prepared via one-pot three component reaction of 2-(4-hydroxy-3-methoxyphenyl)-2-oxoacetaldehyde with dimedone in the presence of hydrazine hydrate and studied by the single crystal X-ray diffraction method. Its structure was also con?rmed by IR, 1H and 13C NMR spectroscopy. Compound 3 was crystallized in the monoclinic system, space group P21/c, a = 7.921(2) ?, b = 11.566(4) ?, c = 16.986(6) ?, B = 107.338(5)°, V = 1485.5(8) ?3, Z = 4, R1 = 0.0559 and wR2 = 0.1253. The crystal structure of 3 also shows a weak interaction between O3 and N2 atoms.

A series of new 2-arylquinoxaline derivatives have been synthesized in high yield by condensation of aryl-1,2-diamines with arylglyoxals in DMF at 50-120 oC.