Novel Routes to Biologically Active Enaminones, Dienoic Acid Amides, Arylazonicotinates and Dihydropyridazines under Microwave Irradiation

Condensation of methylketones 1a,b with dimethylformamide dimethyl acetal (DMFDMA) without solvent in microwave oven afforded enaminones 2a,b, which reacted with malononitrile in ethanolic piperidine to yield dienoic acid amides 7a,b. In contrast, reactions of 2a,b with cyanoacetic acid resulted in the formation of pyranones 10. The pyranones were readily converted into 2-arylhydrazonoketones 13. Condensations of 13 with ethyl cyanoacetate afforded the 5-arylazonicotinates 17. Finally, 2-oxoarylhydrazonals 18 reacted with arylidenemalononitriles 19a,b in presence of chitosan to afford dihydropyridazines 21a,b. In addition the biological activity of the title compounds against Gram positive bacteria, Gram negative bacteria and Yeast were also evaluated.