A concise synthesis and antimicrobial activity of a novel series of naphthylpyridine-3-carbonitrile compounds.

A novel series of acyclic nucleosides 2-5 and 13a-c were synthesized by utilizing 4-phenyl-6(naphthalen-2-yl)-2-oxo-1,2-dihydropridine-3-carbonitrile (1) as a key starting material. Chlorination of 1 yielded the chloro analogue 6 that was allowed to react with urea, thiourea, thiosemicarbazide and alicyclic secondary amines to produce the corresponding derivatives 7a-c and 11a-c. Further condensation of 6 with various amino acids provided the compounds 8-10, whereas hydrazinolysis of 6 yielded the hydrazinyl analogue 12 which was condensed with different isothiocyanates and acid anhydrides to afford derivatives 18-20, respectively. Upon treatment of 12 with sodium nitrite, the azide derivative 14 was obtained which was subjected to reaction with various active methylene compounds to obtain the corresponding triazolo derivatives 15-17. The structure assignment of the new compounds is based on chemicaland spectroscopic evidence. Antimicrobial evaluation of the newly synthesized derivatives was performed using ciprofloxacin and fluconazole as reference antibacterial and antifungal drugs. The most effective compounds against the tested bacterial and fungal isolates were the benzothiohydrazide compound 18b followed by the hydrazone and the phthalic anhydride derivatives 13c and 20, respectively.