Reaction of azolones with acetylene

Conclusions The reaction of 4,5-diphenylimidazol-2-, benzimidazol-2-, and indazol-3-ones with acetylene gave their N- and O-mono- and N,N- and N,O-divinyl derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1882–1885, August, 1988.     

1H- and 13C-NMR study of rotational isomerism in N-vinyltetrazoles

The ¹H- and ¹³C-NMR spectral parameters of N-vinyltetrazoles have been analyzed. It has been found that rotational isomerism is inherent to 1- and 2-vinyltetrazoles. A quantitative estimate of the ratio of rotational isomers has been made. In the case of 1-vinyltetrazoles, introduction of a substituent to the 5-position in the tetrazole ring stabilizes the trans-orientation of the vinyl group relative to the substituent, while in the case of 2-vinyltetrazoles the presence of a substituent in the 5-position of the ring essentially does not affect the conformer population.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1662–1667, December, 1989.     

Estimation of the internal rotation barrier in N-vinylpyrrole by the AM-1, INDO-FPT,and PMR methods

The internal rotation potential of the vinyl group in N-vinylpyrrole calculated by the AM-1 method is predominantly twofold and the barrier itself, corresponding to the gas phase, is 3.8 kcal/mole. Comparison of experimental values of the distant spin-spin coupling constant between protons of the ring and the vinyl group with those calculated using INDO-FPT confirms that the value of the barrier to internal rotation during transition to the liquid phase does not undergo large changes and is in the range 3–5 kcal/mole.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2080–2083, September, 1991.The authors express their thanks to V. F. Sidorkin and V. A. Shagun for kindly providing the INDO-FPT calculation data and for a helpful discussion of the results obtained.     

Reaction of 2-aminobenzimidazole with acetylene

The reaction of 2-aminobenzimidazole (1) with acetylene under pressure proceeds with the formation of vinyl monomers, corresponding to amine and imine forms, 1-vinyl-2-amino- and 1,3-divinyl-2-iminobenzimidazoles, depending on the reaction conditions. 1,3-Divinyl-2-benzimidazolone was also isolated in aqueous dioxane in addition to the monovinyl derivative of1. Cyclization of the divinyl derivative of1 with acetylene proceeds to give 9-vinyl-1,2-dimethylimidazo[1,2-a]-benzimidazole.Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 749–751, March, 1992.     

Extraction of uranium into a third phase of thorium nitrate—tributyl phosphate

Extraction of 0.05–0.25M uranyl nitrate into 30% tributyl phosphate (TBP) in dodecane from nitric acid solutions of thorium nitrate at equilibrium with its salt has been studied. Under investigated conditions a third (second organic) phase is formed. As the heavy organic phase extracts uranium, the calculated ratio of TBP to thorium and uranium sum decreases from 2.7 to less than 7. Electronic spectra show that in heavy organic phase approximately 80% of uranium is found as trinitrate complex, while in the light organic phase this complex is not detected. The measurements of dielectric constant () of the heavy phase reveal a frequency dependence of . The data obtained point to the existence of an ordered structure in the heavy organic phase.     

An unexpected pathway of the reaction of lithiated 1,1-dimethylallene with isopropyl isothiocyanate

The reaction of lithiated 1,1-dimethylallene with isopropyl isothiocyanate gives 3a,4,5,5a-tetrahydro-4,4,5a-trimethyl-2-methylthio-3H-cyclobuta[b]pyrrole resulting from cyclization of the intermediate 2,7-dimethyl-4-methylthio-3-azaocta-2,4,6-triene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 865–867, April, 1997.     

Synthesis of Functionally-substituted Pyrrolothiazolidines from Pyrrole-2-carbodithioates, CH-acids, and Haloacetylenes

Functionally substituted pyrrolothiazolidines have been synthesized by the sequential treatment of pyrrole-2-carbodithioates with methylene-reactive nitriles and haloacetylenes in a KOH-DMSO system.     

Homolytic Addition Reaction of Vinylsulfonylfluorobenzene

The reaction of 3,6-bis(vinylsulfonyl)-1,2,4,5-tetrafluorobenzene with a large excess of tetrahydrofuran at 50-55°C gives the homolytic addition product 3,6-bis[2-(2-tetrahydrofuryl)ethylsulfonyl]-1,2,4,5-tetrafluorobenzene. The reaction is effected by peroxides radical process initiators obtained by the autooxidation of tetrahydrofuran.