o-Nitrobenzoylation of some typical aldehyde and ketone enamines were studied with regard to yields and formation of diacyl derivatives The acylations of butyraldehyde and isobutyraldehyde morpholine enamines were normal and yielded 55% 2-(o-nitrobenzoyl)butyraldehyde and 46% 2-(o-nitrobenzoyl)isobutyraldehyde on acid hydrolysis. 3-Pentanone and 1,3-dimethoxyacetone morpholine enamines on acylation followed by acid hydrolysis gave rise to b-diketone enol o-nitrobenzoates I and II in 37% and 14.8% yields resp. Quite unexpectedly, I and II on acid hydrolysis underwent 1,5- and 1,3-shifts resp. with formation of 3,5-dimethyl-2,6-bis(o-nitrophenyl)-4-pyrone and 2-methoxy-2-methoxyacetyl-1,3-bis(o-nitrophenyl)propane-1,3-dione. Cyclopentanone and cyclohexanone morpholine enamines in contrast to each other on acylation yielded 9% and 45% diacyl enamines III (n = 1, 2) resp. which on acid hydrolysis gave 2-(o-nitrobenzoyl)cyclopentanone and -cyclohexanone in high yields and no acyl shift was detected. Diacylation seemed, therefore, to depend upon steric hindrance as well as conformation.

Key words: NITRO GROUP, BUTYRIC ALDEHYDE P, REARRANGEMENT REACTION, ACID HYDROLYSIS, CYCLOPENTANONE P, CYCLOHEXANONE P, BENZOYLATION, ENAMINES, ISOBUTANAL P, PROPANEDIONE P