Diol lipids

Russian Chemical Bulletin -     

A glucuronosyldiglyceride from an actinomycete

Summary 1. From the sum of the cell lipids of a strain ofStreptomyces producing the antibiotic aureolic acid a glycoside has been isolated which is a 1-O-(-D-glucopyranuronosyl)-2,3-diacylglycerol.2. The trimethylsilyl derivatives of glycerol glycosides have been studied by mass spectrometry. Features of the fragmentation under electron impact of the trimethylsilyl derivatives of the glyceryl glucosides have been determined; the results obtained enable the method of combined gas-liquid chromatography and mass spectrometry to be used for the identification of diacylglyceryl uronosides in lipid fractions.M. M. Shemyakin Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 704–715, November–December, 1973.     

Identification of aliphatic 2- and 3-hydroxy acids in the form of cyclic phenylboronates by GLC-mass spectrometry

A method is prepared for identifying aliphatic 2- and 3-hydroxy acids which is based on the GLC-mass spectrometry of the corresponding phenylboronates. The phenyl-boronates are sufficiently volatile for analysis with the aid of GLC and give simple and informative mass spectra.M. M. Shemyakin Institute of Bioorganic Chemistry, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 283–288, May–June, 1981.     

Sterol glycosides from the Far Eastern holothurianCucumaria japonica

Sterol -D-xylopyranosides and arabinopyranosides in a ratio of 9:1 have been isolated from a lipid extract of the musculocutaneous sac of the Far Eastern holothurianC. japonica. The main components of both glycosidic fractions were identified as derivatives of cholesta-7,22-diene-3-ol, cholest-22-en-3-ol, 5-cholestan-3-ol, 24-ethylcholesta-7,22-dien-3-ol, and 24-methylene-, 24-methyl-, and 24-ethyl-cholest-22-en-3-ols.Institute of Immunology, Ministry of Health of the USSR, Moscow. M. M. Shemyakin Institute of Biorganic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 54, pp. 615–620, September–October, 1984.     

Selective reduction of monoesters of dicarboxylic acids

Summary A new laboratory method was proposed for the synthesis of esters of-hydroxy acids and lactones, based on the selective reduction of the monoesters of dicarboxylic acids with diborane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 369–370, February, 1965     

Adsorption properties of polycrystalline and single crystal electrodes and the influence of surface inhomogeneity

It is shown that the adsorption of some neutral organic compounds on individual faces of a zinc single crystal can be described by the Frumkin-Damaskin theory with the use of the two parallel capacitors model. For a polycrystalline electrode a departure from the two parallel capacitors model is observed which is due to the energetic inhomogeneity of the surface. A method is suggested for calculation of the adsorption isotherm, and of the dependence of the surface coverage θ on the potential of a polycrystalline electrode, from capacity measurements data under the condition that for all n crystallographic faces (grains) exposed on the surface, the difference (C_on ? C′_n) is the same (C_on and C′_n are the double layer capacities in the supporting electrolyte solution and at θ = 1 of the n-th face, respectively). An adsorption isotherm is proposed for a uniformly inhomogeneous surface which takes account of the attractive interaction between adsorbate particles. Some methods are suggested for evaluation of the surface inhomogeneity factor (f). This factor has been determined from adsorption data for cyclohexanol and n-amyl alcohol. The differential capacity curves measured on polycrystalline zinc in the presence of cyclohexanol are in good agreement with the calculated curve for a uniformly inhomogeneous surface.     

Synthesis of two analogues of ubiquinones and their action on mitochondrial respiration

With the aim of obtaining ubiquinone analogues, a fraction of 5-n-alkyl(C₁₉-C₂₅)resoreinols isolated fromAzotobacter chroococcum 92 cells was converted by the action of diazomethane into mono-O-methyl derivatives, which were oxidized with m-chloroperbenzoic acid. The main oxidation products were characterized by spectrophotometric methods as 2-alkyl-6-methoxy-1,4-benzoquinones and 3-alkyl-5-methoxy-1,2-benzoquinomes. Both types of product accelerated the respiration of mitochondria on succinate in a similar way to natural CoQ₁₀, but, in contrast to it, inhibited respiration on an NAD-dependent substrate.Scientific-Research Laboratory of Biologically Active Substances from Hydrobionts, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 172–177, March–April, 1992.