Synthesis and Antifungal Activity of Novel Imidazole Derivatives

Sclerotium rolfsii, an omnivorous soil fungus, is responsible for diseases in a large number of agricultural and horticultural crops, resulting in huge financial losses. Fusarium oxysporum f. sp. melonis, a wilt fungus, is a devastating soil-borne pathogen that causes huge economic losses to the muskmelon crop, hampering not only its production but also affects its fruit quality. There is a need to develop new antifungal agents owing to the increasing resistance in existing fungicides. In the present study, a series of 21 2-imidazolylchromone derivatives 6a–6u were synthesized and characterized with the help of IR, NMR (1H & 13C), and LC-HRMS spectroscopic methods. Out of the 21 synthesized compounds, 17 are reported for the first time in the literature. In vitro fungicidal bioassay results indicated that all synthesized compounds exhibited fungicidal activity against both F. oxysporum and S. rolfsii. Among all synthesized compounds, 6r (6,8-dichloro-2-imidazol-1-yl-chromen-4-one) was found to be the most active against S. rolfsii (ED50 = 6.78 mg L–1) and F. oxysporum (ED50 = 29.72 mg L–1).