Effect of aryl substituents on the rate of dark decolorization of photochromic spirochromenes of the indoline series

The introduction of aryl substituents in the 3 and 7 positions of the indoline spirochromene molecule gives rise to a certain amount of slowing down of dark decolorization in toluene and dioxane; similar changes in the 5, 6, and 8 positions do not change the rate appreciably.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–81, January, 1977.     

Synthesis and photochromic properties of indolinospirochromenes with electron-donor substituents in the indoline part of the molecule

1,3,3-Trimethylspiro(indoline-2,2'-[2H]chromenes) with CH₃ and CH₃O groups in the 4–7 positions and NO₂ and CH₃O groups in the 6 and 8 positions were obtained by the reaction of 4,6-, 4,7-, 5,6-, and 6,7-dimethoxy- and 4-methyl-7-methoxy-2-methyleneindolines and 1,3,3,4,5,6,7-heptamethyl-2-methyleneindoline with 3- and 5-nitrosalicylaldehydes and their derivatives. Most of the compounds have photochromic properties. The introduction of electron-donor groups into the indoline fragment of the spirochromene molecules changes the rate of the dark reaction within the limits of one order of magnitude and has a small effect on the position of the long-wave absorption band of the photomerocyanine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1220–1224, September, 1982.     

Indole fulgides

The syntheses and photochemical properties of fulgides derived from indole and indoline are reviewed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 744–753, June, 1992.     

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.     

Reaction of the fischer base with nitro- and bromo-substituted o-hydroxycinnamaldehydes

The Fischer base reacts with -ethyl-5-nitro-, 5-bromo-, and 3,5-dibromo-2-hydroxy-cinnamaldehydes to give bisindoline spirochromans, with 3-bromo-5-nitro-2-hydroxy-cinnamaldehyde to give a mixture of a spirochroman and a monoindoline merocyanine, and with 3,5-dinitro-2-hydroxycinnamaldehyde to give only a merocyanine. The monoindoline merocyanines obtained do not display a tendency to undergo intramolecular cyclization to give spiro-2H-oxocines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 775–778, June, 1984.     

Photochromic properties of some N-substituted 3,3-dimethyl-6′-nitroindoline-2-spiro-2′-2H-chromenes

A number of photochromic 1-carbethoxymethyl-3,3-dimethyl-6-nitroindoline-2-spiro-2-2H-chromenes were synthesized. The introduction of a carbethoxymethyl substituent at the nitrogen atom instead of a methyl group somewhat increases the rate of dark decolorization of the photomerocyanines without appreciably affecting the spectral characteristics. The results are compared with the analogous spectral-kinetic characteristics of 1-phenyl-substituted compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1640–1644, December, 1977.     

Indole derivatives. 130. Synthesis of disubstituted tryptamines by nitration of 5-methoxy-N-phthalyltryptamine

It was shown that nitration of 5-methoxy-N-phthalyltryptamine in acetic acid gives principally the 4-nitro derivative. The 4-nitro, 4-amino-, and 4-acetyl-amino-derivatives of 5-methoxy-N-phthalyltryptamine were also prepared.For Communication 129 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1050–1053, August, 1987.     

Intramolecular cyclization of 2-hydroxycinnamaldehydes

The effect of substituents on the intramolecular cyclization of 2-hydroxycinnamaldehydes was studied. It was established that aldehydes that contain bulky groups in the side chain and in the 3 position of the benzene ring are readily converted to intramolecular hemiacetals or bimolecular acetals either spontaneously at the moment of isolation or in solutions in DMF or DMSO, as well as on heating. An increase in the lability of the phenolic proton favors the cyclization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 460–465, April, 1988.     

Synthesis and photochromic properties of 5-acetyl-substituted indolinospirochromenes

Four photochromic 5-acetyl-substituted indolinospirochromenes were synthesized. The introduction of an acetyl group does not change the spectral characteristics of the merocyanine form but leads to a decrease in the efficiency of photocoloring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1654–1658, December, 1979Original article submitted January 9, 1979.     

Reaction of a Fischer base and its derivatives with benzoylacetaldehydes

The corresponding 2-(3-benzoyl-2-propen-1-ylidene)indolines, which exist in the form of merocyanines and do not display tendencies to undergo intramolecular cyclization to the spiro form, were obtained as a result of the reaction of 1,3,3-trimethyl-2-methyleneindoline and its analogs with p-substituted benzoylacetaldehydes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 202–206, February, 1981.