The research focused on the photolysis of ortho- and para-substituted aryl azides and the preparation of 2-arylamino-substituted azepines. The best results were achieved in 1,4-dioxane for ortho-substituted azides and in ethanol for para-substituted azides, respectively. It was found that reactions with arylamines, which have electron-donating groups, typically produce higher yields of heterocycles than those with electron-withdrawing groups. Using readily available and cost-effective aryl azides and arylamines, 2-arylamino-substituted 3H-azepines were synthesized via a rapid photoinitiated one-step process. The best results were achieved in 1,4-dioxane for ortho-substituted azides and in ethanol for para-substituted azides. image

The laser material Y3Al5O12 (YAG), originally known in the form of a single crystal, has become widespread and widely commercialized in the form of optical ceramics. The desire to expand by the size effect the functionality of materials made from nanocrystals actualizes studying the influence of their structure on the optical (vibrational and electronic) and other properties of new promising materials with the YAG base, including glass ceramics. In this work, models of crystalline yttrium aluminum garnet fragments have been calculated using the DFT/uPBEPBE/SDD, DFT/uPBEPBE/lanl2DZ, and DFT/uB3PW91/SDD methods. Infrared spectra have been calculated using the DFT/uPBEPBE/lanl2DZ method, and absorption bands at calculated wave numbers have been correlated with the measured ones. The electronic absorption spectrum and level energies have been calculated using the DFT/RB3PW91/SDD method.

A photoinduced one-pot method for the synthesis of azepines by the reaction of aryl azides with 1,3-dicarbonyl compounds under weakly basic conditions is described. This method offers a simple route for the synthesis of 1,3-dicarbonyl-substituted azepines in good to excellent yields and high regioselectivity and was tested on 1,3-dicarbonyl compounds with different acidity levels. The resulting azepines have electrophilic and nucleophilic centers of varying degrees of activity, which facilitate reactions leading to further structural transformations.

The object of the study is ultrafine bismuth barium borate glasses 20Bi2O3–хBaO–(80−х)B2O3, х = 5, 10, or 20 mol % BaO, synthesized using a unique version of the sol–gel method and holding promise for fabricating functional crystalline glass ceramics, in particular, based on yttrium aluminum garnet. A DSC analysis of the obtained charge material with 0.5 μm spherical particles revealed their glassy state at temperaturesof 450–475°C. The presence of glass in particles of such a small size allows the use of the so-called cluster approximation in a quantum-chemical study of the geometric and electronic structure of glasses by the DFT/UB3LYP/LanL2DZ method. Calculated IR absorption spectra are compared with the experimental spectra of the obtained dispersed samples.

The synthetic method of 2-amino-3H-phenoxazin-3-one derivatives through the photoinitiated cyclocondensation of 2-azidophenol with substituted 2-aminophenols was developed. The influence of the starting azide concentration, the solvent nature, and the proportion of water in the reaction mixture on the yield of 2-aminophenoxazin-3-one was studied. A plausible mechanism of the photoinitiated cyclocondensation of 2-azidophenol with 2-aminophenols was suggested.

This study describes a one-pot photoinduced method for azepine synthesis and their subsequent rearrangement into pyridines. The rearrangement of the azepine, formed during photolysis, occurs due to both thermal and photochemical activation of the reaction. This requires an electron-donating substituent at the second position of the azepine and an electron-withdrawing substituent at the third position of the azepine. A reaction mechanism has been proposed to explain the role of water and the nature of the azepine substituents.

— We have developed novel hydrothermal (HT) and hydrothermal microwave (HTMW) processes for the synthesis of nanocrystalline cadmium selenide via reduction using glucose and sodium sulfite. The materials thus obtained have been characterized by X-ray diffraction, CHNS analysis, and electron microscopy. The results demonstrate that they crystallize with a cubic and/or hexagonal symmetry and are nanocomposites containing 14 to 60 wt % organics. Varying synthesis conditions (temperature, composition of the starting mixture, and reaction time) allows one to obtain samples with sizes of coherent scattering regions from 6 to 80 nm. The use of the HTMW process reduces the synthesis time to 15 min in comparison with HT synthesis. The electrical resistance of nanocomposites, measured by the microwave loss method is 10 –4 to 10 –3 Ω cm, which is considerably lower than the resistivity of corresponding CdSe crystals. The data obtained in this work can be accounted for by the presence of carbon-containing components of the composite, which constitute a shell of particles. The increase in the cross-sectional area of “carbon channels” with decreasing nanoparticle size leads to an increase in the electrical conductivity of the material.

Methyl 12-oxo-6,12-dihydroazepino[2,1-b]quinazoline-8-carboxylate and methyl 3H-azepin-2(1H)-one-5-carboxylate were synthesized by photoinduced heterocyclization of methyl 4-azidobenzoate and ethyl 2-aminobenzoate in the THF–water and acetonitrile­–water mixtures. It was found that the yields of methyl 12-oxo-6,12-dihydroazepino[2,1-b]quinazolate increase with rising water content in the reaction mixture.

The effect of an organo-aqueous solvent on the yields of 12-oxo-6,12-dihydroazepino[2,1-b]quinazoline-6-carboxylic acid methyl ester and 3H-azepine-2(1H)-one-3-carboxylic acid methyl ester has been evaluated. It has been found that at low concentrations, water competes with 2-aminobenzoic acid ethyl ester in the nucleophilic addition reaction, reducing the yields of azepino[2,1-b]quinazolinone and increasing the yields of 3H-azepinone. At a water concentration of more than 20 wt %, the nucleophilicity of substituted aniline increases, contributing to an increase in the yields of azepino[2,1-b]quinazolinone and a decrease in the yields of 3H-azepinone.

Azepines are key structural elements of a wide range of pharmaceutically active substances [1]. One of the methods for the synthesis of amino-substituted 3H-azepines is the reaction of nucleophilic addition of amines to 1,2-didehydroazepines C, which are intermediate products of photochemical transformations of aromatic azides (Scheme 1). The photolysis of ortho-arylazides can result in the formation of 2,3and 2,7-substituted 3H-azepines [2]. The ratio of the yields of these azepines depends on both steric [3] and energy [4] factors, which may be due to the specific interaction of azide photolysis intermediates with the solvent. In most cases, the photolysis of azides leads to the formation of 2,3-substituted-3H-azepines [5] as the main products, with 2,7substituted-3H-azepines being either not produced or having low yields. Thus, the aim of this work was to study the effect of the reaction conditions on the efficiency of formation of 2,3and 2,7-substituted 3Hazepines.

2-Азидобензойная кислота в органо-водных средах при облучении в присутствии ацетатов щелочных и щелочноземельных металлов перегруппировывается в 2-[(2-карбоксифенил)амино]-6-формилникотиновую кислоту. Строение полученного соединения установлено методами масс-спектрометрии и спектроскопии ЯМР.

2-Azidobenzoic acid has undergone rearrangement into 2-[(2-carboxyphenyl)amino]-6-formylnicotinic acid under irradiation in aqueous-organic media in the presence of acetates of alkali or alkaline earth metals. The structure of the resulting compound has been elucidated by methods of mass and NMR spectroscopy.

Erratum

The conversion of infrared radiation of a Tm3+:YAP laser at a wavelength of 1.93 mu m into visible light in [(ZrF4)(0.4)-(BiF3)(0.6)](100-x)-(HoF3)(x) (x = 1.5 or 5 wt%) ceramic samples was investigated. The emission bands at wavelengths of 650 nm, 900 nm and 1100 nm corresponding to transitions from F-5(5), I-5(5) and I-5(6) levels to the ground state I-5(8) were observed in upconversion luminescence spectra. From the experimental data, an estimate of the crossrelaxation coefficient from S-5(2) was obtained. It was K-cr approximate to 1 x 10(-16) cm(3) s(-1). The threshold power density of Tm3+:YAP laser, at which a luminescence was observed on the ceramic samples, was about 0.85 W cm(-2).