Studies of Heteroaromaticity. VIII. Reactivity of Some Nitrile Oxides Conjugated with a Double Bond

Abstract

Abstract Phenyl-, furyl-, and 5-nitro-2-furylacrylonitrile oxides were prepared in situ from the corresponding hydroxamoyl chlorides and a base. They reacted with styrene or aery 1 amide as a dipolarophile to give the corresponding 3, 5-disubstituted isoxazolines in very low yields. These results show that the reactivity of such nitrile oxides was reduced by the presence of a conjugated double bond. Phenyl- and 5-nitro-2-furylacrylonitrile oxides were treated with α-morpholinostyrene to afford 3-styryl-5-morpholino-5-phenyl- and 3-(5-nitro-2-furylvinyl)-5-morpholino-5-phenylisoxazole respectively. The former product was further treated with hydrochloric acid to give 3-styryl-5-phenylisoxazole in a good yield. Phenylacrylonitrile oxide was heated in ethanol with cyanoguanidine, leading to 3-styryl-5-guanidino-1, 2, 4-oxadiazole. 5-Nitro-2-furylacrylhydroxamoyl chloride was treated with sodium azide to give the azido-aldoxime.