E. A. Medyantseva

SYNTHESIS, STRUCTURE, AND SPECTRAL AND PHOTOCHEMICAL PROPERTIES OF FULGIDES OF THE INDOLE SERIES WITH AN ADAMANTYLIDENE FRAGMENT

New fulgides of the indole series with adamantylidene fragments were synthesized: 3-(adamant-2-ylidene)-2-[1′-(3′-indolylethylidene)]succinic anhydride (I) and 3-(adamant-2-ylidene)-2-(3′-indolylmethylene)]succinic anhydride (2). By means of electronic absorption and1H NMR spectroscopy and X-ray diffraction analysis, fulgides1 and2 were shown to haveZ- andE-configurations, respectively. The photochemical properties of1 and2 were studied. It was shown that along withZ-E photoisomerization of these compounds, in solution they undergo a cyclization reaction to yield a colored photoproduct. Specific structural features of fulgide1 affecting its photochemical properties were discussed. The introduction of a bulky adamantylidene group decreases the extent of the conversion of compound1 into cyclic isomerC.

Photochromic Fulgides of the Indole and Pyrrole Series

Abstract Novel photochromic fulgides on the base of 3-formyl(acetyl)indole and 2-formyl(acetyl)pyrrole were synthesized and studied. The mechanism of the photoinduced processes in solution and vacuum-deposited films includes: photoreversible (E)-(Z)-isomerization, photo- and thermoreversible cyclizations with the formation of colored dihydrocarbazole and dihydroindoline derivatives which irreversibly convert into uncolored form by 1, 5-hydrogen shift reaction.

The Structure and Photochemical Properties of Novel Fulgides of Indoline Series with an Adamantylidene Fragment

Abstract Two novel fulgides of the indoline series with an adamantylidene fragment have been synthesized and their structure and photochemical properties studied. Whereas adamantylidene - (1′-methyl-3′-indolylmethylene)-succinc anhydride (I) possesses Z-configuration, its homologue, containing a methyl group at the double bond (II), has E- configuration about the C=C bond. The presence of the bulky adamantylidene groups in I and II results in lowering of the photocoloration efficiency compared to respective isopropylidene derivatives.

Structure and photochromic transformations of fulgides of the indole series

Previously undescribed fulgides of the indole series, viz., (1-methyl-3-indolylmethylene)- and (1-methyl-3-indolylethylidene) (isopropylidene)succinic anhydride, were synthesized. A Z conformation for (1-methyl-3-indolylmethylene) (isopropylidene)succinic anhydride and an E configuration for (1-methyl-3-indolylethylidene)-(isopropylidene) succinic anhydride were established by electronic and PMR spectroscopy and x-ray diffraction analysis. The photochromic properties of fulgides were observed and investigated. A scheme of photoinduced and thermal transformations of fulgides that includes a step involving Z → E isomerization in the excited state is proposed. An additional photoisomer was recorded by pulse photolysis and fluorescence.

Structure and ring-chain tautomerism of 3-(1-hydroxy-4-bromo-2-naphthyl)propenal

The previously undescribed 3-(1-hydroxy-4-bromo-2-naphthyl)propenal was synthesized. This aldehyde exists primarily in the form of the cyclic 2H-chromene tautomer in the crystalline state, in solutions in nonpolar solvents, and in acetonitrile, ethanol, and acetone. Ring-chain tautomeric equilibrium between the 2H-chromene and quinoid structures is observed in dimethyl sulfoxide.

Ring-chain tautomerism and thermo- and photochromism of 3-(1-hydroxy-4-methyl-2-naphthyl)propenal imines

A series of previously undescribed 3-(1-hydroxy-4-methyl-2-naphthyl)propenal imines was synthesized. In the crystalline state all of the imines, except the N-(p-nitrophenyl)imine, have an open o-quinoid structure, whereas in solutions in nonpolar solvents they exist in the cyclic 2H-chromene form. In polar solvents the imines display ring-chain tautomeric equilibrium of the 2H-chromene and o-quinoid forms, the relative percentages of which are determined by the character of the substituent in the amino component of the molecule and by the polarity of the solvent. The N-(p-nitrophenyl)imine has-the 2H-chromene structure in the solid phase and in solvents.

Structure and ring-chain tautomerism of 2-hydroxy-5-methyl-3,4-benzocinnamaldehyde

The previously undescribed 2-hydroxy-5-methyl-3,4-benzocinnamaldehyde was synthesized. A cyclic 2-hydroxy-2H-chromene structure in the crystalline state and in nonpolar solvents was established for it by IR, UV, and PMR spectroscopy. It is shown that transition to a polar solvent leads to the establishment of a tautomeric ring-chain equilibrium, the position of which is determined by the type of solvent.

Reactions of heterocyclic cations with nitrogen-containing nucleophiles. 10. Synthesis of 3,5,7-triaryl-1,2-oxazepinium perchlorates by the reaction of 2,4,6-triarylpyrylium salts with nitrones and substituted hydroxylamines

Abstract2-Substituted 3,5,7-triaryl-1,2-oxazepinium perchlorates were obtained by the reaction of 2,4,6-triarylpyrylium salts in dimethylformamide with nitrones and N-arylhydroxylamines. The products are the first representatives of seven-membered cations with eight π electrons.

Photo- and thermochromic 2-amino-2H-chromenes

A number of N-aryl- and N-alkylimines of 2-hydroxy-5,6-benzocinnamaldehyde were synthesized. The cyclic 2-amino-2H-chromene structure in nonpolar solvents was established for them by IR, UV, and PMR spectroscopy. It is shown that the transition to polar solvents leads to the establishment of a tautomeric ring-chain equilibrium. The equilibrium thermal transformations and phototransformations of some N-aryl- and N-alkylimines were studied.