Search

Under phase transfer catalysis conditions, 6-amino-4-phenyl-2-thioxo-1,2-dihydropyridine-3,5-dicarbonitrile (1) was allowed to react with halo compounds, acrylonitrile, chloroacetyl chloride, ethyl cyanoacetate, formamide, triethylorthoformate, or formic acid to give new derivatives of fused pyridines 2–22, respectively. Acetylation of compound 1 using acetic anhydride afforded product 23, which in turn underwent intramolecular cyclization in pyridine to give the corresponding pyrido[2,3-d]pyrimidine 24.

Reaction of dicyandiamide with series of amino acids afforded guanidinyl pyrazolones , respectively. Although reaction of dicyandiamide with urea, acetamide, bezamide, allantion, p-aminobenzoic acid, sulphanilic acid, and adenine gave biguanides , respectively. All compounds have been characterized on the basis of IR and 1H-NMR.

5-Amino-3-anilino-1H-pyrazole-4-carbonitrile 1 was alkylated with various halo reagents under phase transfer conditions to give the corresponding imidazopyrazole derivatives 2a, 2b, 2c, 3, 4, 5, 6. Pyrazolo[1,5-a] pyrimidine derivatives 11, 12, 13, 14 were prepared by treating compound 1 with different dicarbonyl reagents, namely, diethymalonate, ethyl 3-oxo-3-phenylpropanoate, pentane-2,4-dione or ethyl 3-oxobutanoate.

The biologically active compounds of pyrimidine, dihydropyrimidinone, and dihydroimidazole have been synthesized in excellent yield under free solvent conditions. The antibacterial evaluation of the products showed a high inhibitory effect. Reaction of 2-guanidinobenzothiazole with several active methylene compounds has revealed formation of the corresponding pyrimidine, dihydropyrimidinone, and dihydroimidazole derivatives under free solvent conditions in very good yield. All compounds have been characterized on the basis of IR, 1H NMR, 13C NMR, mass spectrometry, and X-ray.

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, 9, 10, 11, 12, 13, respectively. All compounds have been characterized based on IR, 1H-NMR, and mass spectrum.

A new series of tetrahydronaphthalene, isothiachromene, isochromene and isoquinoline derivatives were synthesized by reacting cyclohexylidenemalononitrile with active nitriles, active halo compounds, carbon disulfide, aldehydes, isothiocyanates and isocyanates, respectively.