Reactions of SH-Substituted Purine Bases with Glycidol

The regioselectivity of S-alkylation of SH-substituted purine bases with glycidol tends to grow with decreasing temperature. A procedure was developed for epoxidation of these compounds in wet liquid ammonia. The products were tested for immunostimulating activity.     

Reactions of benzothiazole-2-thione and benzothiazole-2-one with acetylene

Reaction of benzothiazole-2-thione and benzothiazole-2-one with acetylene in the presence of potassium hydroxide or cadmium acetate gives 2-vinylthiobenzothiazole and 3-vinylbenzothiazol-2-one, respectively. Benzothiazole-2-thione is partially convened to benzothiazol-2-one by the action of Cd(OAc)₂. Under vinylation conditions the latter also forms 2-vinylthioaniline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 270–271, February, 1991.     

Stereoselective hydroboration of 5-dimethylaminomethyl-2-methyl-4,5-dihydrofuran: A simple way to (±)-muscarine

Conclusions A fundamentally new scheme was found for the synthesis of (±)-muscarine, in which the required arrangement of all the substituents is achieved in a single step, involving the hydroboration of 5-dimethylaminomethyl-2-methyl-4,5-dihydrofuran.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1383–1386, June, 1989.     

Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance

Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame.     

Determination of catechol derivatives on pretreatment and copolymer coated glassy carbon electrode

A glassy carbon electrode was pretreated electrochemically and was coated with a copolymer of maleic acid anhydride attached with Eastman-AQ55D (MA/AQ). The voltammetric behavior of a series of biologically important compounds, such as dopamine, L-DOPA, DOPAC, ascorbic acid and uric acid were examined at both pretreated and coated electrodes. Electrochemical pretreatment increased peak current of dopamine and L-DOPA while decreased that of ascorbic acid, uric acid and DOPAC. The copolymer coating caused a decrease of peak currents, but effectively hindered the anionic species (ascorbic acid, uric acid and DOPAC) access to the electrode surface. In flow injection and liquid chromatographic analysis. The dopamine and L-DOPA yielded the better selectivity response at MA/AQ electrode than at bare and AQ electrodes.     

Carbonylation reaction Communication 11. Carbonylation of amino alcohols and some cyclic amines with carbon monoxide in the presence of mercuric acetate

Conclusions Primary amino alcohols react with CO in the presence of mercuric acetate at 100–200° and a pressure of 100–150 atm to give the corresponding N-(hydroxyalkyl)formamides in a yield of 1.4–2.5 M/M of reacted Hg(OCOCH₂)₃. Morpholine under analogous conditions forms the corresponding formyl derivative and the urea derivative in a 1.2–51 ratio, while cyclohexylamine forms the same derivatives in an 0.7 1 ratio.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1533–1536, July, 1973.     

Hydrolysis of dimethyl 1-acetoxy-2,2,2-trichloroethyl phosphonate

Conclusions The hydrolysis of chloroacetophos in water includes the parallel cleavage of acetic acid, hydrochloric acid and methanol. The ratio of the products, formed in the parallel steps, was determined, and we also determined the total rate constant for the hydrolysis of chloroacetophos.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2336–2338, October, 1971.     

Sorption of butane, propane, ethane, methane, and carbon dioxide on asphaltene

Isotherms of sorption of butane, propane, ethane, methane, and carbon dioxide on an asphaltene sample of known elemental composition were measured. The effect of the pressure and temperature on the shape the sorption isotherms for all the adsorption systems studied was examined. The values of the initial heat of sorption were determined and compared to the energies of interaction of the molecules with asphaltene. The results obtained suggest that asphaltene is a swellable amorphous sorbent.     

Thermal oxidative degradation of a composition based on a polyester resin and tetramethylammonium chloride

Thermal oxidative degradation of a composition based on a polyester resin modified with rosin and tetramethylammonium chloride and its use as a flux for low-temperature solder pastes were studied.