2-(3-Hydroxy-5,5-dimethylcyclohexylidene)malononitrile 5 undergoes an azo coupling reaction with aryldiazonium salts to afford 3-amino-2-aryl-6,6-dimethyl-8-oxo-2,6,7,8-tetrahydrocinnoline-4-carbonitriles 7. Upon reflux in acetic acid, these compounds were acetylated to give the cinnoline derivatives 9. The pyrazolones 10a, b react with 3-furfurylidene- and 3-thienylidene-malononitrile derivatives 11a, b to afford the pyrano[2,3-c]pyrazole derivatives 13a-d. These newly synthesized compounds show generally a moderate molluscicidal activity to Biomphalaria alexandrina snails.

2-Formyl-2-arylhydrazonoethanenitriles 6b-d where prepared via reacting enaminonitrile 2b,c with aromatic diazonium salts. These reacted with phenylhydrazine to yield bis hydrazones that were converted to arylazopyrazoles via a novel Vilsmeier-Haack reaction type. Reaction of 6c with hydroxylamine afforded oxime that could be successfully cyclised into arylazoisoxazole. Reaction of 6c with hydrazine hydrate to yield arylazoaminopyrazole that proved to be excellent precursors for synthesis functional substituted pyrazolopyrimidines. 2-Arylhydrazonoketones are readily obtained via condensation of arylhydrazines with 1,2-diketone [1,2] or via the coupling reaction of active methylene ketones with aromatic diazonium salts [3][4][5]. 2-Arylhydrazonals (1a) are prepared via coupling enaminones with aromatic diazonium salts, were shown to be excellent precursors to functionally substituted pyridazines [6][7][8], pyrazoles [9][10][11], and condensed azoles [12][13][14].In conjunction to our interest in chemistry of 2-arylhydrazonals 2b [8][9][10][11][12][13][14] as precursors to arylazoaminoazoles for potential utility in dye industry, we report here on the coupling reaction of the enaminonitriles 2b,c with aromatic diazonium salts and results of our investigation aimed at exploring synthetic potentials of these coupling products. The enaminonitrile derivative 2b needed in this investigation was prepared following literature procedure [15] (Figure 1).The newly required enaminonitrile 2c was prepared in 73 % via reacting cyanoacetic acid with triethylorthoformate and piperidine or in better yield (80 %) via reacting 3-ethoxyacrylonitrile (3) with piperidine. 1 H-NMR indicate that the reaction product exists solely in the trans form as it indicated two olefinic protons at δ 4.0 and 7.1 with J = 13.5 Hz typical for trans olefinic protons. Appearance the olefinic proton of H-2 at δ 4.0 ppm is a result of shielding by electron donation from lone pair and cyano group anisotropy.We have found that coupling of 2b with aromatic diazonium salts affords either only formazanes 7 or mixtures of

No abstract

No abstract

The knöevenagel condensation of 3-phenyl-4-thioxo-2-thiazolidinone (1) with 1-phenyl-3-aryl-1H-pyrazole-4-carbaldehydes 2a-d in refluxing glacial acetic acid or in polyethylene glycol-400 (PEG-400) at room temperature without catalyst, afforded the corresponding 5-hetarylmethylene derivatives 3a-d.[4+2] Cycloaddition reaction of compounds 3 with N-arylmaleimides, acrylonitrile and ethyl acrylate afforded thiopyrano[2,3-d]thiazole derivatives 5a-p. The anticancer activity of some of the newly synthesized compounds was investigated against different human cancer cell lines (MCF7 and HEPG2) and confirmed by molecular docking. Moreover, the structure for one representative example of the new products was confirmed by X-ray crystallography. The structure of all the newly synthesized compounds was established by elemental and spectral data.