One-pot synthesis of polysubstituted 1,2,3,4-tetrahydropyridines

Mono- and bicyclic 1,2,3,4-tetrahydropyridine derivatives have been synthesized in up to 98% yield by one-pot three-component condensation of ethyl acetoacetate with methoxymethanol and primary amines (diamines) in methanol in the presence of tert-butyl alcohol.     

On the mechanism of the deflagration-to-detonation transition in a hydrogen-oxygen mixture

The flame acceleration and the physical mechanism underlying the deflagration-to-detonation transition (DDT) have been studied experimentally, theoretically, and using a two-dimensional gasdynamic model for a hydrogen-oxygen gas mixture by taking into account the chain chemical reaction kinetics for eight components. A flame accelerating in a tube is shown to generate shock waves that are formed directly at the flame front just before DDT occurred, producing a layer of compressed gas adjacent to the flame front. A mixture with a density higher than that of the initial gas enters the flame front, is heated, and enters into reaction. As a result, a high-amplitude pressure peak is formed at the flame front. An increase in pressure and density at the leading edge of the flame front accelerates the chemical reaction, causing amplification of the compression wave and an exponentially rapid growth of the pressure peak, which “drags” the flame behind. A high-amplitude compression wave produces a strong shock immediately ahead of the reaction zone, generating a detonation wave. The theory and numerical simulations of the flame acceleration and the new physical mechanism of DDT are in complete agreement with the experimentally observed flame acceleration, shock formation, and DDT in a hydrogen-oxygen gas mixture.     

Efficient Catalytic Synthesis of 2,7-Diaryl(hetaryl)-4,9-dimethylperhydro- 2,3a,5a,7,8a,10a-hexaazapyrenes

A one-pot procedure has been developed for the synthesis of 2,7-diaryl(hetaryl)-4,9-dimethylperhydro- 2,3a,5a,7,8a,10a-hexaazapyrenes by cyclocondensation of aren(hetaren)amines with formaldehyde and 2,6-dimethyl-1,4,5,8-tetraazadecalin in the presence of YbCl₃ · 6 H₂O as catalyst.     

Synthesis of propargyl ethers,possessing bactericidal properties

Conclusions Some derivatives of the propargyl ethers of phenols, possessing bactericidal properties, were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimieheskaya, No. 11, pp. 2591–2593, November, 1968.     

Influence of boric acid on aging of freshly prepared tetraethoxysilane-based gels

The technique for kinetic examination of polycondensation of silicon alkoxides, which allows determining the rate of reaction between ammonium molybdate and various associates of silica for systems in which hydrolysis proceeds, was modified to examine similar systems after the gel point. Aging of freshly prepared tetraethoxysilane-based gels was for the first time studied spectrophotometrically as influenced by boric acid additions. The proportions of various molecular species of silica in the examined systems at different times after the gel point were determined in terms of the kinetic model of the molybdate reaction.