Synthesis and physicochemical properties of some spirochromenes obtained on the basis of 4-azaindoline

The condensation of N-methyl(ethyl)-3,3-dimethyl-2-methylene-4-azaindoline with salicylic acid derivatives was used to synthesize thermo- and photochromic spirochromenes. The kinetics of the spontaneous decolorization of these compounds in ethanol and toluene were studied. The photosensitivity to UV rays of the 4-azaindoline spirochromes is greater by a factor of 1.5 than that of the indoline analogs.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1369, October, 1982.