Synthesis of 5,7-dihydroxy-4,8-dimethylchromen-2-one and its azo derivatives

5,7-Dihydroxy-4,8-dimethylchromen-2-one was synthesized based on methyl phloroglucinol and its spectral and physicochemical characteristics were obtained. Reactions of the newly synthesized coumarin with different diazonium salts were studied, conditions allowing selective obtaining the corresponding monoor bisazo compounds were found. The synthesized azo compounds dye nylon in the yellow-brown colors under standard coloration conditions, providing high stability of obtained colors upon exposure to physicochemical conditions.     

Cosmic-Ray Muon Tomography Setup: Long-Term Life of Drift Tube Chambers

Physics of Atomic Nuclei - For investigation of the cosmic muon scattering tomography (MST) concept at NRC ‘‘Kurchatov Institute’’—IHEP the large-scale setup has been...     

Synthesis of hydroxy-containing terarylenes with pyrazole and allomaltol fragments

Russian Chemical Bulletin - A convenient method for the synthesis previously unknown hydroxy-containing aryl(hetaryl)-ethenes (terarylenes) with a pyrazole bridge was elaborated, which is based on...     

Activity of Nonionic Surfactants

The surface activity of block copolymers of ethylene and propylene oxides, based on ethylenediamine, mono(ethylene glycol), and triethanolamine, was studied. Adsorption characteristics of the investigated compounds at the water-air interface are estimated.     

Dynamic stability of a system of concentric circular domains

The most prominent features of the behavior of domain structures of the “driving center” type were obtained within a simple phenomenological model. It was shown that the external field frequency is a stabilizing factor for such systems.     

Charged current neutrino interactions below 30 GeV

Charged current data of a spark chamber neutrino experiment at the 70 GeV Serpukhov accelerator (10 200 events in the v beam and 3600 events in the $\text{v}$ beam with energies up to 30 GeV) have been analyzed. Total neutrino and antineutrino cross sections and v-distributions are obtained.     

Ultraviolet irradiation of terarylenes: A facile,efficient, and environmentally friendly method for the synthesis of fused polycyclic products

Ultraviolet irradiation of hydroxyl substituted terarylenes provided a simple, efficient, and environmentally friendly method for the synthesis of imidazo[1,2-a]pyridines. The starting terarylenes were prepared via the one-pot, three-component condensation of readily accessible arylglyoxals, 2-aminopyridines, and dimedone.     

Oxidative Cyclization of 5H-Chromeno[2,3-b]pyridines to Benzo[b]chromeno[4,3,2-de][1,6]naphthyridines,Their NMR Study and Computer Evaluation as Material for LED

Oxidative cyclization is one of the most significant reactions in organic synthesis. Naphthyridine derivatives are often used as luminescence materials in molecular recognition because of their rigid planar structure and as new drugs. Organic light-emitting diodes (OLEDs) have rapidly grown as one of the leading technologies for full-color display panels and eco-friendly lighting sources. In this work, we propose the synthesis of previously unknown benzo[b]chromeno[4,3,2-de][1,6]naphthyridines via intermolecular oxidative cyclization of 5-(2-hydroxy-6-oxocyclohexyl)-5H-chromeno[2,3-b]pyridines in formic acid. The investigation of the reaction mechanism using ¹H-NMR monitoring made it possible to confirm the proposed mechanism of the transformation. The structure of synthesized benzo[b]chromeno[4,3,2-de][1,6]naphthyridines was confirmed by 2D-NMR spectroscopy. Such a rigid geometry of synthesized compounds is desired to minimize non-radiative energy losses in OLEDs. The quantum chemical calculations are also presented in the study.