Zobrazeno 1 - 10
of 48
pro vyhledávání: '"B. S. El'yanov"'
Publikováno v:
Bulletin of the Russian Academy of Sciences Division of Chemical Science. 41:1253-1257
The joint action of Lewis acids and high pressure permits the Diels—Alder reaction to be conducted with high yields with greatly sterically hindered steroid dienophiles, which are virtually unreactive under normal conditions. The [2 + 4]-cycloaddit
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 34:1820-1825
1. An equation describing the influence of the pressure on the rate constant of liquid-phase homolytic bond-cleavage reactions has been obtained. 2. A difference in the values of (∂ΔV≠/∂p)p=0/ΔV0≠ in addition and homolytic bond cleavage rea
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 31:2099-2103
The course of the reaction of Δ16-20-ketosteroids with S,S-diphenylsulfylimine depends on the substituent at position 21; it may proceed with cyclization to the 16,17α-epimino-20-ketosteroids, or with formation of 16α-substitutad S-N steroidal yli
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 29:1366-1374
1. The regiospecific 1,3-dipolar cycloaddition of Z- and E-nitronic esters to steroidal Δ16-olefins gives both of the possible diastereomers, which arise as the result of the exo and endo approach of the dipole. 2. In each pair of diastereomers one
Publikováno v:
Tetrahedron. 33:2135-2139
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 33:821-824
Replacement of the 21-acetate group in 3β,21-diacetoxypregna-5,16-dien-20-one by a tetrahydropyranyl group leads to reaction with S,S-diphenylsulfimine with formation of the 16,17α-aziridine.
Autor:
G. A. Stashina, V. M. Zhulin, G. D. Gamalevich, E. M. Vasil'vitskaya, B. S. El'yanov, Edward P. Serebryakov
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 35:302-306
1. It was found that pressure has an accelerating effect on the rearrangement of 3,5-dimethyl-1,5-hexadien-3-ol to 6-methyl-6-hepten-2-one; the volume effect of the activation of this reaction at 180°C, equal to −10 cm3/mole, indicates a concerted
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 33:296-304
1. In reactions of diene condensation of 1-alkyl-substituted dienes with alkyl acrylates, an increase in the radical in the acrylate causes a decrease in the proportion of ortho- and cis-isomers due to steric factors. 2. An increase in the radical in
Autor:
E. M. Vasil'vitskaya, B. S. El'yanov
Publikováno v:
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science. 31:2370-2374
1. The volume activation effect in forward and reverse Diels-Alder reactions does not depend on the electron-donor or electron-acceptor character of the substituent, nor on its strength or its position in the diene. 2. In the absence of significant s
Autor:
A. A. Fainzil'berg, V. S. Bogdanov, V. M. Zhulin, Larisa Melnikova, B. S. El'yanov, Svyatoslav A. Shevelev, Victor V. Semenov
Publikováno v:
Chemistry of Heterocyclic Compounds. 18:859-864
The quaternization of 1- and 2-acetonyl-5-R-tetrazoles, as well as dimethyltetrazole, was accomplished under high pressure conditions (5000–14,000 kgf/cm2) by means of bromoacetone and methyl iodide and at atmospheric pressure and room temperature