INTRAMOLECULAR NUCLEOPHILIC PARTICIPATION .V. ROLE OF ORTHO SUBSTITUENT IN SOLVOLYSIS OF O-NITROBENZHYDRYL BROMIDE AND O-NITROBENZYL TOSYLATE

The capacity of the o-nitro group to serve as an internal nucleophile in the hydrolysis of o-nitrobenz-hydryl bromide and of o-nitrobenzyl tosylate has been investigated. Two experimental observations lead to the conclusion that it is a highly effective participant in the reaction of the former compound: (a) o-nitrobenzhydryl bromide solvolyzes considerably more rapidly in 90% aqueous acetone than does its para isomer; (b) its hydrolysis product is o-nitrosobenzophenone. o-Nitrobenzyl tosylate hydrolyzes somewhat less rapidly than its para isomer, and the evidence is strong that the o-nitro group participates much less extensively in reactions of benzyl than of benzhydryl systems. Good yields of o-nitrobenzhydryl bromide are obtained from the reaction of o-nitrodi-phenylmethane and N-bromosuccinimide in carbon tetrachloride only if the temperature of the reaction is controlled. Otherwise a mixed product is obtained, from which 5-bromo-3-phenyl-2,l-benzisoxazole can be isolated. The reaction paths for production of the benzisoxazole and for formation of o-nitrosobenzophenone by hydrolysis of o-nitrobenzhydryl bromide are considered to have certain features in common. © 1968, American Chemical Society. All rights reserved.