The geometrical structure and energy characteristics of various isomeric forms of cationic spiropyrans were investigated by quantum-chemical approach depending on substituents arrangement in
2H
...-chromene moiety. The energetically preferred structures for stabilization during isomerization process were identified.
Solid-state photochromic indoline spiropyrans bearing a formyl group at the 6′ and 8′ positions of the 2
H
-chromene moiety of the molecules were characterized. The molecular structures of ...spiropyrans were established by single-crystal X-ray diffraction. Intermolecular interactions and voids in the crystals were investigated using the CrystalExplorer17 software package. Further studies of photochromism and mechanochromism of these spiropyrans in the crystalline state are shown to be promising.
The work discusses the mechanism of the formation of by-products during the synthesis of spiropyrans based on 1,3-benzoxazin-4-one heterocycle as a result of the hydrolysis of intermediate styryl ...salt, which explains the low yields of this class of compounds. The structures of the isolated by-products were confirmed by IR and NMR spectroscopy using 2D homo- and heteronuclear experiments, as well as by elemental analysis.
The synthesis of new indoline spiropyran by the cyclocondensation in methanol revealed that the free aldehyde group of the target spiropyran is easily converted into the dimethyl acetal moiety ...without the addition of an acid catalyst, giving 8′-dimethoxymethyl-1,3,3-trimethylspiroindoline-2,2′-2
H
-chromene-5,6′-dicarboxylic acid as a single reaction product. The structure of this compound was confirmed by NMR spectroscopy and mass spectrometry. The molecular structure was also established by single-crystal X-ray diffraction. The Hirshfeld surfaces were generated and analyzed and intermolecular interactions in the crystal were investigated using the CrystalExplorer software package. The reverse hydrolysis reaction of dimethyl acetal to the aldehyde group proceeds under mild conditions in dimethyl sulfoxide, as shown by NMR spectroscopy.
A condensation reaction between formyl-containing spiropyrans and iodides of 1,2,3,3-tetramethyl-3
H
-indolium derivatives was studied. The reaction results in a mixture of products with a strong ...predominance of one of them irrespective of the structure of the starting compounds. The structures of the compounds formed during the reaction were determined based on the NMR, IR, and mass spectroscopy data. The dependence of the yield of the major reaction product on the structure of the starting compounds was studied. The prerequisites for the observed reaction pathway were established and the reaction mechanism was proposed using the results of quantum-chemical calculations based on analysis of the molecular electrostatic potential and the dual descriptor of reactivity.
New indoline spiropyran was synthesized by the cyclocondensation of 5-chlorine-substituted Fischer base with 2,7-dihydroxy-1-naphthaldehyde. This spiropyran was used to prepare a new derivative of ...α-lipoic acid with potential biological activity, which can be considered as a promising photopharmacological agent. The structures of the synthesized compounds were determined by NMR and IR spectroscopy and mass spectrometry and were confirmed by X-ray diffraction. Biological assays using HeLa cells showed that the spirocyclic compounds possess low cytotoxicity even at relatively high concentrations.
Features of the crystal structure of 2-{2-(6′-bromo-1,3,3-trimethylspiroindoline-2,2′-chromene-8′-yl)ethenyl}-1,3,3-trimethyl-3
Н
-indolium perchlorate have been investigated. The studied crystals ...have been grown under different temperature conditions and using different solvent mixtures. Intermolecular interactions and cavities in the crystals have been studied using CrystalExplorer v21.5 software package.
Indoline spiropyran containing an σ-acceptor chlorine atom in 6′ position of the 2
H
-chromene part of the molecule was synthesized and studied. The use of 1,2,3,3-tetramethyl-3
H
-indolium ...perchlorate as a starting compound made it possible to achieve higher product yields as compared to previous studies. The molecular structure of the compound was established by single crystal X-ray diffraction analysis. The features of the crystal structure and intermolecular interactions were investigated using CrystalExplorer17 software package. The photochromic behavior in acetonitrile solution was studied for the first time. It was found that the merocyanine form of spiropyran is characterized by an absorption maximum at 592 nm, which is 37 nm closer to the range of the “biological window” in comparison with the nitro-substituted analog.
This work deals with the study of two derivatives of spiropyrans of indoline series and α-lipoic acid, which are considered as potential photopharmacological agents with controllable biological ...activity. The structure of the compounds has been studied in detail by X-ray diffraction analysis that revealed high lability of lipoic acid fragments. To assess potential biological activity, molecular docking for the possibility of spiropyran molecule to bind to amylin protein in order to inhibit its aggregation has been performed. The results of molecular docking showed a potential increase in the affinity of spirocyclic derivatives toward this protein as compared with α-lipoic acid.
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