Design and synthesis of novel benzoxazole/chromene-phthalide scaffolds hybrids as potential natural products-based fungicide.

Phthalide, benzoxazole, and chromene are important heterocyclic skeletons with extensive biological activities. In order to develop novel potential antifungal agents, twenty-two benzoxazole/chromene-containing phthalide derivatives were prepared, and their fungicidal activity against nine common plants pathogenic fungi were evaluated . The EC values indicated that compound displayed superior antifungal activity against e (11.0 g/mL), (8.5 g/mL), (27.8 g/mL), (3.1 g/mL) and (4.3 g/mL) strains, which was more potent than the two commercialized fungicides hymexazol and chlorothalonil. In addition, the structure-activity relationship analysis demonstrated that the combination site of oxazolamide with phthalide has an important effect on antifungal activity. This research offers a potential compound for the development of novel agricultural fungicides.