الفهرس 
ACKNOWLEDGEMENTOnly 14 pages are availabe for public view
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Abstract
The present research study starts by the preparation of 4,6-dimethyl-2-oxo-1,2-dihydropyridine-3-carbonitrile 1 from acetylacetone and cyanoacetamide. Heating of this pyridone 1 with phosphorus oxychloride furnished 2-chloro-4,6-dimethylnicotinonitrile 2, which underwent refluxing with thiourea to afford 2-mercapto-4,6-dimethylnicotinonitrile 3. Treatment of ethyl 2-((3-cyano-4,6-dimethylpyridin-2-yl)thio)acetate (7) with hydrazine hydrate gave 2-((3-cyano-4,6-dimethylpyridin-2-yl)thio)-acetohydrazide 8. Refluxing of 8 with ethyl acetoacetate furnished 2-((2-(3-methyl-5-oxo-pyrazolyl)-2-oxoethyl)thio)-nicotinonitrile derivative 10, Heating of hydrazide 8 with phenyl isothiocyanate gave 2-(2-((3-cyanopyridin-2-yl)thio)acetyl)-N-phenylhydrazine-1-carbothioamide derivative 13. Heating of (2) with hydrazine hydrate afforded 2-amino-4,6-dimethyl-1H-pyrazolo[3,4-b]-pyridine (19), which underwent chloroacetylation to afford chloroacetamide derivative 23. Cyanoacetylation reaction of 19 with (31) gave 2-cyano-N-(4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl)acetamide (32). The reaction of hydrazide 36 with ethyl acetoacetate furnished 2-((4-(3-methyl-5-oxo-1H-pyrazole-1-carbonyl)phenyl)-amino)nicotinonitrile derivative 38 which reacted with phenyl isothiocyanate and chloroacetone, phenacyl chloride or ethyl bromoacetate to give 2-((4-(4-(3-phenyl-thiazolylidene)-3-methyl-5-oxo-4,5-dihydro-1H-pyrazole-1-carbonyl)-phenyl)amino)-4,6-dimethyl-nicotinonitriles 42a, 42b and 43. In general, all synthesized pyridine scaffolds revealed better activity against the Gram-positive bacterium (B. subtilis) rather than the Gram-negative bacterium (E. coli).