13C NMR spectra of a number of penta- and hexacyclic triterpenoids derived from glycyrrhetic acid

The¹³C NMR spectra of 22 derivatives of 18α- and 18β-glycyrrhetic acids that have been investigated and an assignment of the signals has been made. It has been shown that a modification of the carboxy group of glycyrrhetic acid leads mainly to a change in the chemical shifts of the α-, β-, and γ-carbon atoms of ring E. The assignment of a number of signals has been confirmed by the use of the shift reagent Eu(fod)_s. It has been established that the C₂₈ and C₁₆ signals are the most sensitive to a change in the C₁₈ configuration in the spectra of glycyrrhetic acid derivatives.

     

Telomerization of alkane- and arenesulfonamides with butadiene catalyzed by palladium complexes

Conclusions The catalyzed (by palladium complexes) telomerization of butadiene with butane- and p-toluenesulfonamides, which leads to difficult-to-obtain N-substituted unsaturated sulfonamides in high yields, was realized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 372–376, February, 1985.     

Sulfur ylides. 3. Synthesis of keto-group stabilized amino-containing sulfur ylides from amino acids

An effective path of synthesis was developed of new synthetic intermediates, the optically active, keto-group stabilized amino-substituted sulfur ylides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 612–620, March, 1990.     

13C NMR spectra of biologically active compounds.

The¹³C spectra of 25 new substituted cyclopropanes of the pyrethoid series have been investigated and a stereochemical assignment has been made of the stereoisomers formed. As the criterion for stereochemical assignment it is proposed to use the values of the chemical shifts for the -carbon atoms of the substituents in the cyclopropane ring.Institute of Chemistry, Bashkir Branch, USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 266–272, March–April, 1989.     

Direct metallation of cyclic conjugated hydrocarbons by highly reactive magnesium

Conclusions Organomagnesium compounds have been prepared by the direct metallation of cyclopentadiene, indene, fluorene, and cyclooctatetraene and by highly reactive magnesium. Their crosscombination with allyl and propargyl electrophiles in the presence of metal complex catalysts has been studied, this leading to the allyl and propargyl substituted hydrocarbons being obtained in high yields.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 428–431, February, 1988.     

Ozonolysis of Alkenes and Study of Reactions of Polyfunctional Compounds: LXVII. Synthesis of 27,27,27-Trifluoro-20-hydroxyecdysone Acetonides from 24,25- and 25,26-Anhydro-20-hydroxyecdysone Derivatives via Ozonolysis and Trifluoromethylation

Ozonolysis of 24,25/25,26-anhydro derivatives of 20-hydroxy-2,3:20,22-di-O-isopropylidene-ecdysone and 2,3-di-O-acetyl-20-hydroxy-20,22-O-isopropylideneecdysone, followed by trifluoromethylation of the corresponding 25-oxo derivatives afforded 2,3:20,22-di-O-isopropylidene- and 20,22-O-isopropylidene-27,27, 27-trifluoro-20-hydroxyecdysones.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 387–395.Original Russian Text Copyright © 2005 by Odinokov, Savchenko, Afon’kina, Khalilov.For communication LXVI, see [1].     

Molecular and crystal structure of 5Z-carboxymethylene-2-chloro-4,4-dimethoxy-3-N,N-dimethylaminocyclopent-2-en-1-one

In the crystal, the 5Z-carboxymethylene-2-chloro-4,4-dimethoxy-3-N,N-dimethyl-aminocyclopent-2-en-1-one molecule has an intramolecular hydrogen bond (stabilized in the chelate form) between the proton of the carboxy group and the oxygen atom of the keto group. The methoxy groups are in an antiperiplanar conformation and are synclinal with respect to the dimethylamino group and the double bond of the carboxylmethylene fragment. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1979–1981, November, 1997.