Preparation of N-methacryloxyethyl derivatives of spiropyrans of the indoline series

Reaction of 2,3,3-trimethylindolenine with ethylene iodohydrin gave 1-hydroxyethyl-2,3,3-trimethylindoleninium iodide, which gives 3a,4,4-trimethyloxazolidino[3,2-a]indoline on treatment with sodium carbonate solution. Condensation of the latter with 5-nitro- and 3-methoxy-5-nitrosalicylaldehydes gives, respectively, N-hydroxyethyl derivatives of 6-nitro- and 6-nitro-8-methoxyspiro(indoline-2,2-benzopyrans) (V, VI), while condensation with 3-nitrosalicylaldehyde gives 4,4-dimethyl-3a-(2-hydroxy-3-nitrostyryl)oxazolidino[3,2-a]indoline (VII). Acylation of nitrospiran V and oxazolidinoindoline VII with methacrylyl chloride in pyridine proceeds at the free hydroxyl groups, while a mixture of derivatives of 1-(-methacryloxyethyl)spiropyran and 3a-(2-methacryloxy-3-nitrostyryl)oxazolidinoindoline is formed under the same conditions from nitromethoxyspiropyran VI. Acylation of V in acetone in the presence of sodium bicarbonate gives 4,4-dimethyl-3a-(2-methacryloxy-5-nitrostyryl)oxazolindo-[3,2-a]indoline. The mechanism of the isomeric transformations of the various forms that contain spiropyran and oxazolidino-indoline rings was studied by means of electronic spectra. The photochromic properties of the spiropyrans were investigated.Communication VI from the series Photochromism of Organic Substances. See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1362–1369, October, 1973.     

Carbocyanine dyes with an o-hydroxyaryl substituent in the meso position of the polymethine chain

Carbocyanine dyes with an o-hydroxyaryl substituent in the meso position of the polymethine chain were obtained from o-hydroxybenzoyl derivatives of the Fischer base and heterocyclic methylene bases (1,3,3-trimethyl-2-methyleneindoline, 1-ethyl-4-methylene-1,4-dihydroquinoline, and 1-methyl-2-methylene-1,2-dihydroquinoline) in the presence of phosphorus oxychloride. The symmetrical indolenine dyes exist in the colorless spiropyran form in an alkaline medium. The unsymmetrical carbocyanines with a quinoline fragment do not form a spiro form and are deeply colored compounds; this is explained by their open dipolar structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 100–103, January, 1988.     

Synthesis of 4-nitro-3,3,7-trimethyl-2-(2-hydroxystyryl)indolenines

The previously unknown hydroxystyrylindolenines have been synthesized by the direct condensation of 4-nitro-2,3,3,7-tetramethylindolenine with substituted salicylaldehydes. The structure of the prepared compounds has been confirmed by spectroscopic investigation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 340–342, March, 1990.     

Photochromic fulgides based on 2-acetyl-1-methylindole

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 856–857, June, 1989.     

Heterocyclic fulgides based on 1,2-dimethyl-3-formylindole

Nonphotochromic fulgides of the indole series, which undergo E, Z isomerization under UV irradiation, were obtained from 1,2-dimethyl-3-formylindole and esters of aryl- and alkylmethylene-substituted itaconic acids by Stobbe condensation in the presence of strong bases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 201–205, February, 1989.     

Influence of substituents in salicylaldehyde molecule on interaction with 2-imino-3,5-dimethylthiazolidine

Salicylaldehyde, 5-chlorosalicylaldehyde, or o-vanillin will react with 2-imino-3,5-dimethylthiazolidine to form previously unknown bis(3,5-dimethylthiazolidin-2-ylideneamino)-2-hydroxyphenylmethanes. If strong electron-acceptor groups are present on the aromatic ring, an acid-base interaction takes place. Thus, 3-nitro-5-methoxy-, 3-nitro-5-chloro-, and 3-bromo-5-nitrosalicylaldehyde react with the heterocyclic base to form saltlike complexes, the structure of which has been confirmed by x-ray diffraction.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 420–425, March, 1993.     

Intramolecular hydrogen bonding with the participation of the nitrogen atom of five- and six-membered heterocycles

A comparison of the frequencies of the valence vibrations of the OH group and of the chemical shifts of the protons of the hydroxyl groups in -naphthol derivatives containing the nitrogen atom of the condensed ring of pyridine, pyrazine, 1,2,5-selenadiazole, 1,2,5-thiadiazole, 1,2,5-oxadiazole, and imidazole in the peri position to the hydroxyl group is indicative of the decisive effect of the molecular geometry on intramolecular hydrogen bonding in systems with rigidly fixed configurations. All conditions being equal, the intramolecular hydrogen bond is considerably weaker when the nitrogen atom is part of a five-membered rather than a six-membered heterocycle. This is explained not only by an increase in the distance between the proton donor and acceptor (which may be the same in some cases), but also by the greater deviation of the orbital of the unshared electron pair of the nitrogen of the five-membered heterocycle from the O...N line and, thus, by its greater distance from the hydrogen atom. For the same favorable molecular geometry, the OH...N bond is stronger than the OH...O bond because of the high basicity of the nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 238–244, February, 1971.