Rhodium-Catalyzed Double Dearomatization of 1,2,3-Triazole-Isoxazole Dyads: Synthesis of Nonfused 1-1,3-Diazepines.

A double dearomatization of dyads consisting of 1-sulfonyl-1,2,3-triazoles and 3-aryl-5-methoxyisoxazoles was applied for the efficient synthesis of nonfused 1-1,3-diazepines. The plausible mechanism of the cascade reaction includes transformation of the 1,2,3-triazole to rhodium azavinyl carbene, the -selective hydride shift to form the 1-azabuta-1,3-diene moiety, rhodium-catalyzed ring contraction of the isoxazole to azirine, and pseudopericyclic four-atom ring expansion of the azirine. The synthetic utility and antiproliferative activity of the 1,3-diazepines obtained have been demonstrated.

Gold vs Light: Chemodivergent Reactivity of Diazoesters toward 2-Azirine-2-carboxylic Acids.

An orthogonal reactivity of diazo compounds toward azirine-2-carboxylic acids, switching with the reaction conditions, is demonstrated. A gold-catalyzed reaction is N-selective and produces 1,3-oxazin-6-ones, whereas a blue light activation leads to O-H insertion products, azirine-2-carboxylic esters. The observed chemodivergence is explained by the metal-bound and metal-free carbenes exhibiting different electronic properties in these reactions.

Characteristics of Epoxy Composites Containing Carbon Nanotubes/Graphene Mixtures.

The paper considers the development of fillers representing mixtures of carbon nanotubes and graphene materials (graphene oxide and graphene nanoplatelets) in different mass ratios to modify epoxy resin. The graphene type and content effect on the dispersed phase particle effective sizes-both in aqueous suspensions and the resin-was analyzed. Hybrid particles were characterized by Raman spectroscopy and electron microscopy.

Synthesis of Imidazo[1,2-]pyridines via Near UV Light-Induced Cyclization of Azirinylpyridinium Salts.

An efficient one-pot synthesis of imidazo[1,2-]pyridines from 2-bromoazirines and pyridines has been developed. The construction of the bicyclic framework of imidazo[1,2-]pyridines occurs in two steps through the formation of (2-azirin-2-yl)pyridinium bromides followed by dehydrobrominative UV light-induced cyclization. The method can also be applied for the synthesis of imidazo[2,1-]isoquinolines.

Light-induced one-pot synthesis of pyrimidine derivatives from vinyl azides.

A one-pot procedure for the synthesis of tetrasubstituted dihydropyrimidine and pyrimidine derivatives from α-azidocinnamates was developed. The synthesis is based on the finding that the outcome of LED photolysis of α-azidocinnamates depends on the light wavelength employed. Blue light (455 nm) leads to the formation of 2H-azirines only, but violet light (395 nm), UV-A light (365 nm), or sunlight result in the transformation of the in situ formed 2H-azirines to 1,3-diazabicyclo[3.

New concept of pathogenesis of impaired circulation in traumatic cervical spinal cord injury and its impact on disease severity: case series of four patients.

Purpose: The purpose of this study is to justify a new concept of the pathogenesis of secondary changes in the cervical spinal cord, and its correlation with the depth of development of neurological disorders in spinal injury.

Methods: Standard magnetic resonance imaging examination and angiography of the cervical and vertebral arteries of four patients were performed to diagnose the prevalence rate of ischemia and edema, and examine the spinal cord vasculature. Correlation of the data obtained with the neurological status was performed.

[Prophylaxis of wound infection with immobilized antibacterial drugs].

New drug ambipor that is an immobilized antibacterial agent with local prolonged therapeutic activity was developed for prophylaxis of wound suppuration. In ambipor A drugs gentamicin, dioxidin, kephzol and riphampicin are immobilazed, in iodopor - iodine. Experimental studies on 455 white rats showed that ambipor prevents suppuration, abscess formation around ligatures, improve regeneration and fibrillogenesis.

Mean characteristics of lidar signals from broken clouds.

The problem of the backscattered laser radiation field formation is solved based on the theory of optical radiation transfer in broken cloudiness as a scattering medium with random geometry. The dependence of the energy characteristics of a lidar return averaged over the ensemble of cloud-field realizations on the type of clouds (cumulus and stratus), cloud fraction, optogeometrical parameters of a cloud field, lidar's geometric parameters, and the distance to a cloudy layer. It has been shown that over long periods the multiple light scattering between the cumulus clouds is the dominating contribution to the lidar signal power.

Preparation and results of a 24-hour orbital flight.

The space age presents man with unprecedented opportunities for discovery and for cooperative endeavors to benefit all mankind. My flight of August 6-7, 1961 was conducted for the purpose of determining whether man can stay and work effectively and whether all systems of the spaceship can operate successfully during a period of 24 hours in space. The flight of Vostok II represents an experimental step in a logical sequence which included the first earth orbiting flight of USSR citizen Yuri A.