Photoinduced bimolecular cyclization of diarylamines with polyhalomethanes into acridines

It is shown on the basis of measurements of the activation parameters for the reaction of nucleophilic substitution, an intermediate stage of photochemical reactions, that the entropy factor makes the main contribution to the decrease in the reactivities of the intermediates that occurs on going from CHBr₃ to CBr₄ The low efficiency ofN-alkyl-substituted diarylamines in these photochemical transformations is explained by taking into consideration another intermediate stage (cyclization) and by quantum chemical modeling of the preceding isomerization.For Part 3, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 663–667, April, 1995.