Mechanism of the photoreactions of fulgides based on 1,2-dimethyl-3-formylindole

Only E Z isomerization is observed for the steady irradiation of fulgides based on 1,2-dimethyl-3-formylindole in contrast to the analogs based on 3-acetylindole. The formation of cyclic photoisomers is registered by the method of impulse photolysis. The presence of a methyl substituent in the position 2 of the indole portion leads to a significant increase in the stability of the photochromic system. The introduction of alternative reaction centers of cyclization in the form of bulky phenyl groups leads to the suppression of electrocyclization at the position 2 of the indole portion and the formation of dihydronaphthalene structures.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1255–1258, September, 1991.