Part I.~Reduction of azoalkanes by benzhydryl radicals. Part II.~Thermolysis and photolysis of an alpha-aminoazoalkane, 2-tert-butylazo-2-dimethylaminopropane. Part III.~A reinvestigation of the photochemistry of trifluoromethylazocyclopropane
Engel, Paul S.
Master of Arts
Benzhydryl radicals donate a hydrogen atom rapidly to the less hindered nitrogen atom of aliphatic and aromatic azo compounds, leading to the corresponding hydrazines. When the initially formed hydrazyl radical possesses a weak $\beta$ bond, it undergoes scission before receiving a second hydrogen atom. An unsymmetrical $\alpha$-aminoazoalkane, 2-tert-butylazo-2-dimethylaminopropane (3c) has been prepared by reaction of 2-tert-butylazo-2-chloropropane (4c) with dimethylamine. A photolysis and thermolysis study revealed that this azoalkane is unusual because it is sensitive to acid and protic solvents. Normal homolysis of 3c in nonpolar solvents allows assessment of the radical stabilizing ability of the dimethylamino group. The solution phase photolysis of trifluoromethylazocyclopropane (1) has been reinvestigated. The results showed that this azocyclopropane undergoes the same primary photoreactions as the other azocyclopropanes that have been studied. It is concluded that the original work on 1 is seriously in error. (Abstract shortened with permission of author.)
Organic chemistry; Physical chemistry