Formation and crystal structure of 5-[hydroxy(phenyl)amino]-3,3,5-trimethyl-2-phenylisoxazolidine and N-(3,3,5-trimethyl-2-phenylisoxazolidin-5-yl)phenylaminyl N-oxide (Banfield and Kenyon's radical)
The product formed by the reaction of acetone with N-phenylhydroxylamine is (VI), 5-[hydroxy(phenyl)amino]-3,3,5-trimethyl-2-phenylisoxazolidine, and the corresponding stable free-radical (Banfield and Kenyon's radical) is (VII), N-(3,3,5-trimethyl-2-phenylisoxazolidin-5-yl)phenylaminyl N-oxide, and not N-(1,1-dimethyl-3-phenyliminobutyl)phenylaminyl NN′-dioxide or N-[1,1-dimethyl-2-(3-methyl-2-phenyloxaziridin-3-yl)ethyl]phenylaminyl N-oxide as was previously thought. The crystal structure of two crystal forms [(A) and (B)] of (VI) has been determined by direct methods and refined by block-diagonal least-squares to R 0·093 (A) and 0·098 (B). In both forms the space group is P21/n, with Z= 4; for (A) : a= 12·45(1), b= 13·25(1), c= 10·18(1)Å, β= 97·7°(1); and for (B) : a= 13·96(1), b= 7·37(1), c= 16·14(1)Å, β= 94·1°(1). The molecular shape is the same in both types.