| Abstract: | The corresponding merocyanines, which do not display a tendency to form spiropyran structures, are formed in the condensation of 1,3,3-trimethyl-2-methyleneindoline with 5-methyl-2-furoylacetaldehyde, 2-formylcyclohexanone, or 2-formyl-1-tetralone. Spiran compounds in which the spiropyran—merocyanine equilibrium is shifted markedly to favor the closed form are formed when 4a,9-dimethyl-2,3,4,4a-tetrahydrocarbazone — the cyclic analog of the Fischer base — is used in the reaction with salicylaldehydes and benzoylacetaldehydes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1205–1210, September, 1982. |
