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Notes: Reactions of Aziridino-nitrenes: Synthesis of Polycyclic Bisaziridines and 1,2-Bisaziridino-diazenesVorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in Bern am 7.Oktober 1977.7-Amino-7-azabicyclo[4.1.0]-3-heptene (11b), cis-9-amino-9-azabicyclo[6.1.0]-nonane (12b), cis-9-amino-9-azabicyclo[6.1.0]-(4Z)-nonene (13b), as well as exo- and endo-3-amino-3-azatricyclo[3.2.1.02,4]-6-octene (14b and 15b) were synthesized by addition of oxidatively generated phthalimido-nitrene (6) to 1,4-hexadiene, (Z)-cyclooctene, (1Z,5Z)-cyclooctadiene, and bicyclo[2.2.1]heptadiene, respectively, followed by hydrazinolysis of the corresponding N-phthalimido-aziridines 11a-15a.Lead tetraacetate oxidation of the two unsaturated N-amino-aziridines 11b and 15b at -70° yielded diazapolycyclic structures by intramolecular addition of the intermediate aziridino-nitrenes 11c and 15c to the δ, ε-situated C, C-double bond; the products obtained in good yields were 1,5-diazatetracyclo [3.3.0.02,8. O4,6]-octane (16) and 3,7-diazapentacyclo [3.3.1.02,4.03,7.06.8] nonane (17), respectively Oxydation of the unsaturated N-amino-aziridine 13b under the same conditions did not cause intramolecular addition of the nitrene 13c to the ε, ζ-situated C, C-double bond; instead 1,2-bis (cis-9-azabicyclo [6.1.0]-(4Z)-nonen-9-yl)-diazene (20) was obtained in low yield and (1Z, 5Z)-cyclooctadiene as the main product. Both products can be rationalized as derived from the intermediate nitrene 13c with 13b and the olefine as the result of a fragmentation of 13c under extrusion of N2. As. expected, oxidation of the saturated N-amino-aziridine 12b led to the 1,2-bisaziridino-diazene 21 and (Z)-cyclooctene in a ratio of 4:6. Surprisingly, oxidation of 7-amino-7-azabicyclo [4.1.0]-heptane (10b) produced only fragmentation of the corresponding nitrene 10c to cyclohexene. Finally, oxidation of the exo-N-amino-aziridine 14b yielded a complex not yet resolved product mixture in low overall yield. Attempts to add the oxidatively generated aziridino-nitrene 12c to cyclohexene, methyl acrylate, and dimethylsulfoxide were without success.Heating the 1,2-bisaziridino-diazenes 20 and 21 at their respective m.p. temperatures caused thermal fragmentation to occur with evolution of nitrogen. The bisaziridines 26 and 28 as well as the aziridines 27 and 29, respectively, were isolated. These products could be the result of a radical pathway, whereas a small amount of (Z)-cyclooctene, also generated in the thermolysis of 21, might be formed by a competing cheletropic pathway.The 1H-NMR-spectra of the derivatives of cis-9-azabicyclo[6.1.0]nonane, namely of 12a, 12b, 21, 28 and 29, showed signals for some of the aliphatic protons which were separated from the others at relatively low field (around 2.5-1.8 ppm). These signals accounted for 4 (with 12b for 2) protons in each of the cis-9-azabicyclo[6.1.0]nonane subunits, i.e. more than the 2 expected for the aziridine methine protons. The additional signals must be assigned to methylene protons (2 or even 4 of them) probably situated on the other side of the eight membered ring and deshielded by the motion-average proximity to the aziridine nitrogen atom.

Notes: 3,3-Dialkyltriazenecarboxylic Derivatives by Oxidative Hydro-Acyl-Elimination from 3,3-Dialkyltriazane-1,2-dicarboxylic DerivativesThe preparation and some properties of esters and amides of 3,3-dialkyltriazenecarboxylic acids (6) are described. These novel triazenes 6 were obtained by treatment of diesters, diamides and ester-amides of 3,3-dialkyltriazane-1,2-dicarboxylic acids (3) with lead tetraacetate, when an elimination of the COOR- or the CONHR-group at N(2) together with the H-atom at N(1) took place. The precursor triazanes 3 were readily available from the addition of secondary amines 2 to diesters, diamides or ester-amides of diazenedicarboxylic acid (1). The spectral properties of the triazanes 6, including the 15N-NMR signals of one example, are compared with those of the triazanes 3. They express the structural features due to conjugation in 3,3-dialkyltriazenecarboxylic derivatives, including the resistance to rotation around the N(2), N(3)-bond.

Notes: The Product of Hydrogenation of a β-Nitro-N-nitrosoamine Is Not a 1,2,3-Triazolidine, but a β-Hydroxylamino-N-nitrosoamineIt is shown, by spectroscopy, that the product of catalytic hydrogenation of N, 2-dimethyl-2-nitro-N-nitrosopropylamine (1) consists of a 5:1 mixture of (E)- and (Z)-2-hydroxylamino-N, 2-dimethyl-N-nitrosopropylarnine (3) and does not contain - as had been claimed - any l, 2-dihydroxy-1, 2, 3-triazolidine (2). Thus there is still no evidence for the existence of the N(OH)N(OH) functionality. The structure of intermediates on the way to 1 are also revised.

Notes: 1,2,3-Triazolidines by Cycloaddition of Azimines to OlefinesAzimines A can undergo [3+2]-cycloadditions with olefines B to give 1,2,3-triazolidines C, a class of hitherto unknown heterocycles. The three examples of this reaction realized here involved the azimine 1 with electron-withdrawing substituents and the olefines 2, 3 and 4 with an electron-donating substituent, yielding the cycloadducts 5,6 and 7. The triazolidine structure of 5 was established by an X-ray diffraction analysis. Characteristic for 5 are also: (a) that the three N-atoms are pyramidal (and thus centers of chirality), (b) that the five-membered heterocycle takes on a twist (half-chair) form, and (c) that the regioselectivity of the cycloaddition places the (E)-substituent of the olefine 2 vicinal to the terminal (Z)-substituent of the azimine 1. On this basis the constitutions of 6 and 7 are assigned. The spectral properties of the triazolidines 5, 6 and 7, including the 15N-NMR signals of one example, are compared with those of the related triazane 12.

Notes: Azimines. VIITeil VI, s. [1]. . Preparation by Oxidation of TriazanesA novel method for the preparation of certain azimines 4 by oxidation of 1,2,3-trisubstituted triazanes 3 is described. Treatment of 3-aryl-triazane-1,2-diesters 3a-3c with lead tetraacetate afforded the 3-aryl-azimine-1,2-diesters 4a-4c. The precursor triazanes 3a-3c were prepared by addition of p-substituted anilines to diisopropyl diazene-1,2-dicarboxylate 1b. A comparison of the spectral properties of the azimines 4 with those of the correspondingly substituted triazanes 3 reveals the unsaturated and dipolar nature of the azimines 4.