SYNTHESIS OF FUNCTIONALIZED CYCLIC NITRONES VIA REGIOSELECTIVE AND UNUSUAL [3-NITROSOSTYRENES WITH 1,3-DIAZABUTA-1,3-DIENES AND IMINES(2]CYCLOADDITIONS OF ALPHA)

The alpha-nitrosostyrenes 2, generated in situ from a-halogeno oximes, undergo regioselective [3 + 2] cycloaddition with 1,3-diazabuta-1,3-d ienes 1 and 5 leading to the cyclic nitrones 3 and 6, respectively, Si milarly, the cyclic nitrones 12 are also formed in reactions of 2 with the trisubstituted amidines 11, Thermolysis of the nitrones 3 and 12d -f gives imidazole derivatives 13, The nitrones 6, on the other hand, on thermolysis under similar conditions, give the amidine derivatives 17, Interestingly, the treatment of both 3 and 6 with NaBH4 in methano l and the reactions of 2 with N-arylbenzamidines also yield the imidaz ole derivatives 13.