1-Naphthyl-2-cyanoacetamide in heterocyclic synthesis: synthesis and evaluation of the antimicrobial activity of some new pyridine, pyrimidine, and naphtho[2,1-b]oxazine derivatives

Abstract

1-Naphthyl-2-cyanoacetamide 1 reacts with arylidene malononitrile to afford a novel 2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile derivative 6. Heating of 1 under reflux with the 1,3-diketones acetylacetone and benzoylacetone furnished the corresponding 3-cyano-2-pyridones derivatives 7 and 8, respectively. Fusion of 1 with 2 mol malononitrile afforded pyridinylacetamide 9. Condensation of 1 with nitrosonaphthols or salicylaldehyde afforded naphthoxazines 11 and 13, or chromene 17, respectively. Coupling of 1 with 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-diazonium chloride gave the hydrazone 15, which cyclized with acetic acid to afford the corresponding pentaaza derivative 16. Treatment of 1 with DMF–DMA gave acrylamide 19, which when reacted with hydrazine hydrate, o-phenylenediamine, thiourea, or guanidine hydrochloride to afford the corresponding 3-aminopyrazole, diazepine, and pyrimidine derivatives 20, 21, 22, and 23 respectively. The newly synthesized compounds were characterized by elemental analysis and use of spectral data (IR, 1H NMR, 13C NMR, and MS).The newly synthesized compounds were tested for their in-vitro antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. The results clearly showed that most of the synthesized compounds had mild to moderate activity against the bacteria.