Reaktionen von Aziridino‐nitrenen: Herstellung von polycyclischen Bisaziridinen und von 1,2‐Bisaziridino‐diazenen
Authors: Hoesch Lienhard , Egger Notker , Dreiding André S. 
Published: December 2004

Reactions of Aziridino‐nitrenes: Synthesis of Polycyclic Bisaziridines and 1,2‐Bisaziridino‐diazenes

Vorgetragen 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.