SYNTHESIS AND X-RAY STUDY OF HEXAHYDROPHOSPHOLO[2,3-D]ISOXAZOLES AND TETRAHYDROPHOSPHOLO[2,3-D]ISOXAZOLES, A NEW CLASS OF HETEROCYCLES OF POTENTIAL FUNGICIDAL ACTIVITY

Hexahydro-, 5b-1 and 6a,f,l and tetrahydropho spholo[2,3-d]isoxazoles 8, 9 and 10 were synthesized by 1,3-dipolar cycloaddition of nitrones 3b-1 and benzonitrile oxide (4) to 2,3-dihydro-1-phenyl-1H-phosphole 1 -oxide (1) and 2,3-dihydro-1-ethoxy-1H-phosphole 1-oxide (2). The stru ctural assignment to the compounds was confirmed by an X-ray study of two compounds of the series 5a and 5m. The compounds show a good activ ity as fungicides against Plasmopara viticola on vines and against Bot rytis cinerea on apples. Compounds 5a-d showed weak to moderate activi ty as herbicides.