Reactions of monothiooxamides with O-methylhydroxylamine

The reactions of monothiooxamides with O-methylhydroxylamine were studied. Depending on the substituents in monothiooxamides, the reactions result in the formation of hydroxamic acid derivatives or various N-methoxy derivatives of amidoximes.     

Reactions with Addition Compounds Containing Activated Formic Acid

Addition compounds of formic acid with tertiary organic bases in ratios higher than that required for salt formation (3:1 and 2:1 adducts) contain formic acid in a highly activated form. In particular, the 3:1 adducts of formic acid with trimethylamine and triethylamine are liquid reducing agents that are convenient to handle and are suitable for use in many selective reductions. These addition compounds have a surprisingly strong reducing action on sulfur dioxide, which is rapidly converted, even at low concentrations, into crystalline rhombic sulfur. Sulfones and polysulfones can be prepared in good yields by three-component reactions from activated formic acid, sulfur dioxide, and polarized vinyl compounds.     

Synthesis of a novel 18β-glycyrrhetinic acid derivative

A novel compound, biotinylated 18β-glycyrrhetinic acid (BGA), was synthesized. It is a compound of 18β-glycyrrhetinic acid linked with biotin. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 266–267, May–June, 2006. An erratum to this article is available at .     

无保护流体室温燐光法测定吲哚-3-丁酸的研究

在仅以碘化钾为重原子微扰剂、亚硫酸钠为除氧剂及无任何保护性介质存在的水溶液中 ,吲哚_3_丁酸 (IBA)能发射很强的室温光 (RTP) ;详细研究了分析测定条件及有机溶剂对RTP的影响 ;在最大光波长λex/λem =281/447nm处 ,光强度与IBA浓度在2.0×10 -7～1.0×10 -5mol/L范围内呈良好的线性关系 ,检出限4.3×10-8 mol/L ;方法直接用于强化水样和土壤中IBA的测定 ,回收率96 %～104 % ,相对标准偏差2.37 %～3.97 %。     

Effects of <Emphasis Type="Italic">L</Emphasis>-Carnitine on Sucrose-Induced Hyperlipidaemia

Summary. L-Carnitine, L-(−)-β-hydroxy-γ-trimethylaminobutyrate, plays an important role as a factor necessary for the transport of long-chain fatty acids into the mitochondria. In order to investigate the influence of L-carnitine on hyperlipidaemias, the experimental model of the sucrose-induced hypertriglyceridaemia of the rat was used. In these experiments L-carnitine in the dose of 11 mg per day and 100 g body weight (over the period of 1 week) was able to antagonize the sucrose-induced hypertriglyceridaemia and the increase of serum free fatty acid level in female rats of the Wistar strain. Carnitine administration did not change the activities of lipogenic enzymes and fatty acid synthesis in the liver. However, L-carnitine increases the rate of hepatic fatty acid oxidation. Our results indicate a hypotriglyceridemic and free fatty acid lowering effect of L-carnitine, and suggest the use of this compound in the therapy of hyperlipidaemias.     

Characterization of Saccharomyces Sp. through determination of amino acid profiles by capillary gas chromatography

The Saccharomyces strains uvarum, montuliensis, bayanus, capensis and florentinus were grown in liquid media prepared from a 1% aqueous glucose solution to which 0.05% of ammonium sulfate or urea were added as the only nitrogen supply. The amino acids exuded during incubation were isolated by cation exchange and derivatized as the corresponding N,O-heptafluorobutyryl isopropyl esters. Separation was achieved on a highly deactivated glass capillary column coated with OV-101. A characteristic amino acid profile was obtained for each of the species studied, allowing the construction of a chemotaxonomic tree, on the basis of present or absent acids.     

Interaction of (1-phenylethyl)indole-2-carbonitrile with C-nucleophiles

Methods of obtaining ketones and enamino esters have been developed on the basis of reactions of 1-(1-phenylethyl)indole-2-carbonitrile with organomagnesium and organozinc compounds. Removal of a benzyl group from the indole nitrogen atom by the Grignard reagent has been discovered. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1179–1183, August, 2006.     

Investigation of the phosphinyl analog of α-ketoglutaric acid

It was shown by³¹P and¹³C NMR spectroscopy that methyl(3-carboxy-3-oxopropyl)phosphinic acid (4-methylhydroxyphosphinyl-2-oxobutyric acid) (1) and the amide (2) of the latter exist in keto forms in non-aqueous solutions. In aqueous solutions an equilibrium between the keto,gem-diol, and enol forms has been observed. The proportions of the diol and enol forms increase as the acidity of the media increases. Silylation of acid 1 with hexamethyldisilazane gives the tris(trimethylsilyl) derivative of enol form (3) (Z- andE-isomers).Translated fromIzyestiya Akadetnii Nauk. Seriya Khimicheskaya, No. 1, pp. 125–128, January, 1994.     

Voltammetry in Undiluted Acetic Acid. In Situ Determination of Water

Water present in undiluted acetic acid can be monitored in situ with Pt and Au microelectrodes using differential pulse and square‐wave voltammetries. Both reduction and oxidation peaks can be obtained. The best quantitative analytical results were obtained for the anodic peak, the Pt microelectrode, and differential pulse voltammetry. The anodic water peak is located at +1.55 V vs. the quasi reference Pt electrode. The voltammetric peak obtained at Pt electrode is apparently not a diffusional one, however, the calibration plot obtained by employing this peak is linear over a wide concentration range, up to 4 mol dm^?3. The detection limit has been estimated as 2.3 mM or 0.0043 v/v%. The developed method may be particularly useful, since the Karl Fischer method can not be used to determine water in glacial acetic acid due to the estrification reaction of acetic acid with methanol. A voltammetric wave of undiluted acetic acid could not be obtained in the positive and negative ranges of potential.     

The direct conversion of carbamates to ureas using aluminum amides

The conversion of carbamates into ureas using aluminum amide complexes is reported. This reaction is a convenient method to prepare bi-, tri- and tetra-substituted ureas from carbamate-protected primary or secondary amines by reaction with primary or secondary amines in the presence of stoichometric quantities of trimethylaluminum. A reactivity trend of the various carbamates was observed and methyl and benzyl carbamates were reacted selectively in the presence of t-butyl carbamates.