PERACID INDUCED RING-OPENING OF SOME ISOXAZOLIDINES AND OXIDATION OF SATURATED 1,3-OXAZINES TO NEW HETEROCYCLIC NITRONES

The regiochemistry of peracid-induced ring opening of a number of isox azolidines is investigated. The mechanism of the ring opening reaction and the effects of substituents on the regiochemical behavior have be en discussed. The oxidation profess gives an equilibrium mixture of ni trone and its six-membered ring hydroxylamine tautomer; the ratio of w hich is round to depend on the substituents. The tautomeric cyclic hyd roxylamine has been converted to a new class of nitrones by oxidation with mercury (II) oxide or p-benzoquinone. One of the cyclic hydroxyla mine lacking hydrogen at the alpha-carbons has been oxidized to nitrox ide spin label. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.