Synthesis and Characterization of 2‐Pyridylsulfur Pentafluorides

Current approaches to prepare SF₅‐substituted heterocycles during the synthesis of targeted heterocyclic compounds require the use of SF₅‐functionalized aryl or alkyne reagents or SF₅Cl as a source of the SF₅ functional group. Herein we report that excess oxidative fluorination of 2,2′‐dipyridyl disulfide with a KF/Cl₂/MeCN system leads to the formation of thirteen new 2‐pyridylsulfur chlorotetrafluorides (2‐SF₄Cl‐pyridines). These molecules are found to undergo further chlorine–fluorine exchange reactions by treatment with silver(I) fluoride enabling ready access to a series of ten new substituted 2‐pyridylsulfur pentafluorides (2‐SF₅‐pyridines). This is the first preparatively simple and readily scalable example of the transformation of an existing heterocyclic sulfur functionality to prepare SF₅‐substituted heterocycles.     

The evolution of states and phase transitions under cooling of the early universe within the two-Higgs-doublet model

The two-Higgs-doublet model (2HDM) realizes ground states (vacuum) with different properties for different parameter values. The parameters of the effective potential change during cooling of the Universe after the Big Bang. In so doing, the properties of vacuum state can be affected, phase transitions take place. The evolution of phase states and the set of phase transitions can turn out to be much wider than those accounted for within the conventional Standard model (SM) with a single Higgs doublet. The phase history of the Universe is analyzed for any specified set of the 2HDM parameters. All possible variants of the history are considered. Sets of modern, observed, in principle, parameters corresponding to different sequences of thermal phase transitions are determined. Possible cosmological consequences are briefly discussed.     

On the dependence of the critical crystallization rate on the initial impurity concentration in melt

The dependence of the critical crystallization rate on the initial impurity concentration in melt is derived by determining the condition at which a nonplanar solution to the stationary diffusion problem arises. It is suggested that the conditions at which defects arise at the interface differ from those obtained when crystallization becomes stationary. The initial transient process of binary melt solidification under crystal pulling at a constant rate has been studied numerically within a 1D model. It is shown that the character of the time dependence of the crystallization rate is determined by the ratio of the crystal pulling rate to solidification rate V _c, when a constitutional supercooling zone is formed in the melt.     

The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acids

Conclusions The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acid leads to the formation of 1,2-disubstituted and condensed adamantane derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2515–2521, November, 1979.     

Investigation of the alkylation of nitroazoles with α-haloketones by13C,15N,and14N NMR

General methods have been worked out for the alkylation of nitroazoles with bromoacetone, bromoacetophenone, and diazoacetone in homogeneous media and by phase-transfer catalysis. The structures of the N-acetonylazoles were established by¹³C,¹⁵N, and¹⁴N high-resolution NMR spectroscopy.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1827–1837, August, 1990.     

4-Aryl(benzyl)sulfonyl-2-chloro-5-polyfluoroalkyl-1,2,3-triazoles. The first monocyclic N-chloro-1,2,3-triazoles

Treatment of 4-aryl(benzyl)sulfonyl-5-polyfluoroalkyl-v-triazoles with NaOCl gave the 4-aryl(benzyl)-sulfonyl-2-chloro-5-polyfluoroalkyl-v-triazole derivatives which contain a chlorine atom only on the N₍₂₎ atom of the heterocycle. The structure of 2-chloro-5-(1,1,2,2,3,3-hexafluoropropyl)-4-(p-tolyl-sulfonyl)-2H-[1,2,3]triazole has been established by X-ray structural investigation. The presence of a highly polarized N—Cl bond with a positive halogen atom causes the N-chlorotriazoles to react with KCN and KF as strong acids to form the potassium salts of the triazoles and to form 4-arylsulfonyl-2-(2-chloro-1-ethoxyethyl)-5-polyfluoroalkyl-2H-[1,2,3]triazoles with vinyl ethyl ether. It was found that chlorination of 4-arylsulfonyl-5-polyfluoroalkyl-v-triazoles in the presence of KF gives 4-chloro-5-polyfluoroalkyl-2H-[1,2,3]triazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1342–1352, September, 2007.     

Nitropyrazoles 14. Synthesis of 1,3,4-trinitropyrazole and its behavior in the nucleophilic substitution reactions. General method of synthesis of 5-substituted 3,4-dinitropyrazoles

For the first time pyrazole containing three nitro groups in the pyrazole cycle, viz., 1,3,4-tri-nitropyrazole, was obtained by N-nitration of 3,4-dinitropyrazole. 1,3,4-Trinitropyrazole enters the cine-substitution reaction of N-nitro group under the action of 0-, N-, and C-nucleophyls under mild conditions. Thus, general method of synthesis of 5-substituted 3,4-dinitropyrazoles containing free NH fragment was worked out.     

Reaction of 1,5-hydride shift in acylation of propyne by cis and trans isomers of 2-methylcyclohexanoyl tetrafluoroborate

Conclusions The reaction of propyne with the cis and trans isomers of 2-methylcyclohexanoyl tetrafluoroborate proceeds with the formation of the products of 1,5-hydride shift, in which connection its direction depends on the configuration of the reagent.Translated from Izvestiya Akadmii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 243–246, January, 1978.