Abstract
A series of novel pyridine-connected piperidine derivatives (2a-g) and pyridine-connected 2H-thiopyran derivatives (4a-g) were synthesized and evaluated for larvicidal, nematicidal, and antimicrobial activities. Compound 4e exhibited larvicidal activity against second instar larvae with an LD50 value of 0.8 mu g/mL. In addition, 4e was most effective against root knot nematode Meloidogyne javanica, with an LD50 value of 3.2 mu g/mL. Compounds 2e (MIC: 4 mu g/mL) and 2d (MIC: 4 mu g/mL) exhibited high antibacterial activity against Klebsiella pneumonia, and Escherichia coli, respectively. Compounds 4b (MIC: 0.25 mu g/mL) and 4f (MIC: 2 mu g/mL) showed high antifungal activity against Candida albicans and Microsporum audouinii, respectively. Therefore, overall activity profiles envisages that compounds 2e, 2d, 4e, 4b, and 4f could be employed for the development of new classes of drugs with larvicidal, nematicidal, and antimicrobial activities.