The A1-l, 2-diazetines 1 and 2 have been synthesized in three steps from N- methyltriazoliiedione (MeTAD) and the olefins (adamantylideneadamantane, Ad-Ad, for 1; 7- norbornylidene-7-norbomane for 2). Diazetidme 3 (from Ad-Ad+ MeTAD) undergoes ring expansion to a pyrazolidine derivative, 5 (subsequently converted to a novel pyrazoline, cyclic (five-ring) azo compound 6). The structurallyrelated N-methylaminocarbonyl ...