SYNTHESIS OF 4H,6H-FURO[3,4-C]ISOXAZOLE DERIVATIVES AS NEW POTENT FUNGICIDES AND THEIR STRUCTURE-ACTIVITY RELATIONSHIP

4H,6H-Furo[3,4-c]isoxazoles (I-IV), potential fungicides, have been de signed and synthesized via intramolecular [2+3] cycloaddition of nitro alkyne 3 as a key step. The broad spectrum of fungicidal activities of furoisoxazoles (I-IV) were observed on plant pathogens at 250 ppm. Fu roisoxazoles II, III with chlorophenyl at 6-position and methyl or alk ylated osime group at 3-position gave effective control of plant disea ses. The furoisoxazole IV with a chlorophenyl group at 4-position also resulted in high fungicidal activities.