Russian Journal of Organic Chemistry, Vol. 36, No. 6, 2000, pp. 836-842. Translatedfrom Zhurnal Organicheskoi Khimii, Vol. 36, No. 6, 2000, pp. 869-874. Original Russian Text Copyright 9 2000 by Kuznetsov, Kuznetsova, Schantl. Oxidative Addition of N-Aminophthalimide to Conjugated Azoalkenes. Synthesis of the First C-Azoaziridines M. A. Kuznetsov 2, L.M. Kuznetsova 1, and J. Schanti 2 tSt. Petersburg State University, St. Petersburg, 198904 Russia ~J.Schantl lnstitut fiir Organische Chemie, Universitiiet Innsbruck lnnrain 52a, A-6020 lnnsbruck, Austria; e-mail: Joachim.Schantl@uibk.ac.at Received February 9, 1999 Abstract--The oxidation of N-aminophthalimide with lead tetraacetate in the presence of I~-phenylazostyrene or 1-phenylazocyclohexene results in phenylazo-l-phthalimidoaziridines, the first among derivatives of C-azoaziridines. 1-Phenylazopentene yields quite different product, 2-phenyl-2,4,5,6-tetrahydrocyclopenta[d]- 1,2,3-triazole. From 2-phenylazapropene was obtained a mixture of the corresponding triazole and N-[2- (phenylhydrazono)propylidenamino]phthalimide, but the same reaction with the cyclic azoalkene, 3,3,5-tri- methyl-3H-pyrazole, afforded the mixture of three regio and stereoisomeric phthalimidoazimines. Oxidation of N-aminophthalimide and of a number similar N-amino heterocycles with lead tetraacetate in the presence of compounds containing C =C bond is a general preparative procedure for various N-amino- aziridine derivatives (the so-called "oxidative amino- aziridination") [1-5]. On the other hand, under the same conditions occurs oxidative addition of the N-aminophthalimide to azocompounds resulting in a new class of polynitrogen 1,3-dipoles, phthalimido- azimines [3, 6]. For over 20 years these both reac- tions were regarded as proceeding with intermediate participation of the corresponding aminonitrenes. However in 1987 Atkinson showed that at least under common conditions of the oxidative aminoaziridina- tion, below 0~ aziridines are formed via another intermediate, N-acetoxyhydrazine, and no amino- nitrenes take part in the process (see discussion in [3-51). Disregarding the type of intermediate taking part in both reactions it was interesting to compare the reactivity of C =C bond and azo group by carrying out the process with substrates containing both reac- tion sites, first of all, with conjugated azoalkenes. Therefor in this study we investigated oxidation of N-aminophthalimide with lead tetraacetate in the presence of easily available (E)-l-phenylazoalkenes [7-9] and 3,3,5-trimethyl-3H-pyrazole [10] that contained the conjugated azo group in Z-configuration (preliminary communication see [11]). The composition of the products turned out to be strongly dependent on the structure of the initial azo compounds. For instance, from 13-phenylazostyrene and 1-phenylazocyclohexene we obtained the cor- responding phenylazo-l-phthalimidoaziridines (I, II), derivatives of C-azoaziridines prepared for the first time. Ph Ph NN=N Phth---NH2- ")q=N + PhtlflqH N NphPb(OAc) 4 tN'~ ph31% PhthN I, 38% PhthN Ph Ph Phth--- NH2 I \ N " N'=N~L ~ + PhthNH N----% Pb(OAc) 4 ~_J 24% X____J II, 51% O PhthN-- - ~ N ~ 0 Phenylazoaziridines I and II are lemon-yellow crystalline compounds; they are stable at room temperature for no less than several weeks, but they decompose at heating. Their composition is confirmed by elemental analyses, and the structure by spectral data. The typical of many derivatives of N-amino- aziridine slow inversion of the aziridine nitrogen [12] is revealed in the 1H and 13C NMR spectra of 2-phen- yl-3-phenylazoaziridine (I) by appearance of two sets of signals belonging to syn- and anti-invertomers in 1070-4280/00/3606-0836525.00 9 MAIK "Nauka/Interperiodica"