Certain asymptotic characteristics of groups

Translated from Matematicheskie Zametki, Vol. 46, No. 6, pp. 85–93, December, 1989.     

Addition of xanthate ions to diacetylene

Conclusions S-(1-Buten-3-ynyl) alkylxanthates were obtained by reacting diacetylene with CS₂ in an alcohol-KOH system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2808–2811, December, 1982.     

Effects of conjugation and the conformational structure of aromatic selenides

Conclusions In the aromatic selenides, in contrast to the corresponding sulfides, the partial steric inhibition of the conjugation of the Se atom with the aromatic -system occurs. The appreciable content (30%) of the plane conformer is observed in compounds with the tertiary and quaternary -carbon atoms of the alkyl group; this explains the weak -donor properties of Se in relation to the aromatic fragment.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 64–69, January, 1989.The authors thank V. M. Bzhezovskii for helpful discussions, as well as V. I. Mamatyuk, R. G. Kostyanovskii, and I. I. Chervin for allowing the possibility of registering the¹³C NMR spectra of some of the investigated compounds.     

Protonated forms of N-vinylpyrroles

The reaction of N-vinylpyrroles with hydrogen chloride at low temperatures has been studied. At –80C the -position of the heterocycle is protonated while at higher temperatures products of HCl addition to the double bond and protonation of the ring are formed. The C-Cl bond of the chloroethyl radical of the product of HCl addition to the vinyl group is readily dissociated resulting in reversible interconversion of the enantiomers of the racemic mixture which is formed. By introducing a diastereotopic marker (i-Pr) this interconversion can be monitored by dynamic NMR. It has been found that the energy of this process varies with HCl concentration and with the substituents on the ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 334–338, March, 1988.     

Synthesis of 2-indolylacetic acid derivatives

2-Indolylacetic acid derivatives were synthesized by condensation of diethyl acetonedicarboxylate with α-substituted arylhydrazines under the conditions of the Fischer reaction, and their transformations were studied.