Mechanistic studies of a linear trisazoalkane, a new azimine, and a bicyclic triaziridine. Azoalkane homolysis into seven fragments
An aliphatic azo compound containing three azo groups (1) has been prepared by IF(5) oxidation of beta-azoamine 3. The thermolysis kinetics of this vicinal trisazoalkane were investigated above 155 degrees C, leading to a rate constant only 5.5 times faster than that of the simple model, azo-tert-butane. Because thermolysis to form seven stable products proceeds stepwise, the rate is hardly affected by the high exothermicity of the overall reaction (-93.4 kcal/mol). Oxidation of amine 3 also afforded a cyclic azimine 5 that underwent photolysis to yield a highly strained triaziridine 9 plus an unusual triazane 10, whose structures were elucidated by detailed NMR studies. On standing at ambient temperature, 9 reverted to 5 with a half-life of about an hour.
Engel
PS
Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
Pan
L
Whitmire
KH
Guzman-Jimenez
I
Willcott
MR
Smith
WB