Determination of the structure of acetates of N-arylglycosylamines of disaccharides according to their mass spectra

Conclusions The mass spectra of acetates of N-arylglycosylamines of disaccharides with various types of bonds were studied. The acetates of N-arylglycosylamines are convenient derivatives for the mass spectrometric analysis of disaccharides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1030–1040, May, 1973.     

Mass spectra of functional derivatives of sterically hindered olefins

Conclusions Study has been made of the mass spectra of certain functionally substituted sterically hindered phenols. It has been found that the presence of functional groups in the aromatic ring p-position generally has no effect on the fragmentation pattern. More complex substituents (-COR, -COOR, -CH₂Hal, -CH₂CH₂Hal, etc.) can be involved in the fragmentation process.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2686–2693, December, 1976.     

Iron-catalyzed Doyle-Kirmse reaction of allyl sulfides with (trimethylsilyl)diazomethane

[formula: see text] Iron salts efficiently catalyze the Doyle-Kirmse reaction of allyl sulfides with (trimethylsilyl)diazomethane and ethyl diazoacetate in dichloroethane at 83 degrees C. Competitive dimerization is less of a problem with (trimethylsilyl)diazomethane than with ethyl diazoacetate. Good results are obtained using only 1.5 equiv of (trimethylsilyl)diazomethane, even without slow addition. Phosphine ligands affect the kinetics, but not the diastereoselectivity. Dppe and BINAP lead to higher yields than dppp, but no enantioselection was detected with R-(+)-BINAP.     

Using FTIR spectroscopy to detect sericin on historic silk

Silks represent some of the most precious ancient and historic textile artefacts in collections worldwide.Their optimum preservation demands an appreciation of their characteristics.One important concern,especially with regard to ancient Chinese silks,is whether the fabrics have been degummed.Silks with remnant sericin gum coating the fibroin fibres would require different conservation protocol.In previous research on aged silks,the presence of sericin has been inferred from amino acid analysis of hydrolysa...     

Reactivity of molecules with nitrogen-containing functional groups toward H+ and SiMe3 + ions

The equilibrium constants of trimethylsilyl cation transfer reactions differ from those of proton transfer reactions by many orders of magnitude. The basicity of MeCN (1), MeNO₂ (2), and Et₂NH (3) in the gas phase decreases in the series3≫1>2, whereas the affinity of the same compounds for trimethylsilyl cation decreases in the series1≫3≈2. Semiempirical quantum-chemical MNDO calculations indicate that the formation of MeCN·SiMe₃ ⁺ ions is thermodynamically more favorable than that of MeNH₂·SiMe₃ ⁺ ions. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1260–1261, June, 1998.     

Glycosylation of dibutyl phosphate anion with arabinofuranosyl bromide: unusual influence of concentration of the reagents on the ratio of anomeric glycosyl phosphates formed

Russian Chemical Bulletin -     

Specific features of the interaction of methyl ethers of methyl (methyl-α-D-galactopyranoside)uronate with trimethylsilyl ions in the gas phase

Specific features of the interaction between trimethylsilyl ions and methyl (methyl-α-d-galactopyranoside)uronate and its methyl ethers were revealed. It was shown that a hydrogen atom is generated when the trimethylsilyl ion is located at hydroxyl group. This atom migrates over the methoxy and hydroxyl groups toward the glycoside methoxy group, resulting in the formation of [Me+SiMe₃−MeOH]⁺ ions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1317–1319, July, 1997.