O-Glycosylation/Alkylation and Antimicrobial Activity of 4,6-Diaryl-2-Oxonicotinonitrile Derivatives

摘要

A series of glycosylation and alkylation reactions of 6-phenanthernyl-2-pyridone derivatives 1a, b containing electron withdrawing and electron donating substituents at 4-position is reported. Regioselective 2-O-alkylated/glycosylated products were obtained exclusively, irrespective of the electronic nature of alkylating or the glycosyling agent. Glycosylation of 1a, b with glucosyl/galactosyl and lactosyl bromides afforded 2a, b; 4a, b; and 6a, respectively. Alkylation of 1a, b with epichlorohydrin, propargyl, allyl bromides, and 3-chloropropanol resulted in compounds 8-10 and 13, respectively. Deprotection of O-glycosylated products under conventional conditions provided the free glycosides 3a, b; 5a, b; 7a, 12; and 13, respectively. The minimal inhibitory concentration for some of the newly synthesized compounds showed high significant activity against Gram (+ve) and Gram (-ve) and antifungal activities. Among the screened compounds, the 4-trifluromethyl phenyl derivatives 2a, 3a, 4a, 8a, and 11a exhibited strong antimicrobial activity.