A general method for the preparation of 4- and 6-azaindoles

Nitropyridines reacted with an excess of vinyl Grignard reagent to produce 4- or 6-azaindoles. Improved yields were obtained when a halogen atom was present at the position alpha to the nitrogen atom in the pyridine ring.     

Catalytic cathodic stripping voltammetry of oxidized glutathione at a hanging mercury drop electrode in the presence of nickel ion

Oxidized glutathione (GSSG) can be determined after previous accumulation on the HMDE at E > -0.2 V (vs. the Ag AgCl reference electrode). GSH is formed during the accumulation, possibly by a mercury-ion-assisted hydrolytic disproportionation of GSSG. In the subsequent cathodic scan GSH is released and catalyses the reduction of nickel ion, giving a peak located at -0.6 V. This enables the determination of GSSG by differential-pulse cathodic stripping voltammetry at pH 7.0 in the phosphate acetate or MOPS buffer containing 0.5-1.0 mM Ni(II). The detection limit is 10 nM. The calibration graph is linear even in the presence of small amounts of human serum albumin, HSA. However, HSA increases the detection limit (20 nM for 3 x 10(-4)% HSA). Acetyl-cysteine in small excess or Cu(II) present as reagent impurity do not interfere. Glutathione, cysteine and similar compounds, which accumulate as mercury salts and form stable nickel complexes, will interfere. The method is put forward as a novel alternative stripping voltammetric method to those involving accumulation and determination as mercury or copper salts and complexes, in the knowledge that it may have advantages in particular analytical situations. In particular the method discriminates against compounds which accumulate as mercury salts but which do not form stable nickel complexes.     

Structural refinements of praseodymium and neodymium orthophosphate

The crystal structures of PrPO₄ and NdPO₄ have been determined by single crystal X-ray diffraction techniques. The structures are isostructural with CePO₄ and LaPO₄, and are monoclinic in space group $\text{P2}{}_1\text{n}$. The cell constants are a = 6.741(3), b = 6.961(4), c = 6.416(3) Å, and β = 103.63(3)° for PrPO₄ and a = 6.722(1), b = 6.933(1), c = 6.390(2) Å, and β = 103.72(2)° for NdPO₄. The least-squares structural refinements of PrPO₄ and NdPO₄ yielded R values of 0.034 and 0.038 based on 810 and 947 unique reflections, respectively. The lanthanide metal atoms are coordinated with nine oxygens and are linked together by very slightly distorted tetrahedral phosphate groups. The nine oxygen atoms ligating the lanthanide atoms form a polyhedron that is best described as a pentagonal interpenetrating tetrahedron.     

Insect pheromones and their analogs. VIII. Synthesis of the (Z) and (E) isomers of 2-methyloctadec-7-ene and of 2-methyl-7,8-epoxyoctadecane

A highly stereospecific method for the synthesis of racemic (Z)-disparlure has been developed which is based on the reduction of 2-methyloctadec-7-yne with the aid of 9-borabicyclo[3.3.1]nonane and the epoxidation of the resulting (Z)-2-methyloctadec-7-ene with p-methoxycarbonylperbenzoic acid. The¹³C NMR spectra of the (Z) and (E) isomers of 2-methyloctadec-7-ene and 2-methyl-7,8-epoxyoctadecane, which unambiguously confirm the structures of these compounds, are given. It has been established that (E)-2-methyloctadec-7-ene exhibits a moderate attractant activity while the (Z) isomer does not attract the gypsy moth. The addition of 5–25% of (E)-disparlure increases the biological activity of (Z)-disparlure.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 630–634, September–October, 1983.     

Isomerization of S-2-hydroxyalkyl esters of cyclic phosphorus thioacids

Conclusions The S-2-hydroxyalkyl esters of cyclic P(V) thioacids, which were obtained by reacting a cyclic phosphorus monothioacid with an alkylene oxide, are converted to the 2-mercaptoalkyl esters of cyclic phosphorus acids independent of the size of the ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2594–2596, November, 1980.     

Polysaccharides of brown algae IV. Fragmentation of the molecules of sargassan and pelvecyan

Summary It has been shown that the molecules of sargassan and pelvecyan each contain a linear high-molecular-weight fragment consisting of residues of glucuronic acid and mannose alternating with one another.Institute of Biologically Active Substances, Far Eastern Scientific Center, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 393–396, July–August, 1971.     

Simultaneous thermogravimetric and thermo-gastitrimetric investigations under quasi-isothermal and quasi-isobaric conditions

The derivatograph has been modified to provide a new technique with the help of which the weight change of a sample and the amount of the evolving gases can be determined as a function of the temperature of the sample under quasi-isothermal and quasi-isobaric conditions. The thermal decompositions of potassium and sodium hydrogencarbonate were investigated; it was established that under special conditions the otherwise one-step thermal decomposition of the two materials becomes a two-step process. The phenomenon involves a change only from the point of view of kinetics, for the decomposition itself does not split into two consecutive processes.     

Mechanical properties and molecular mobility in oriented polyolefines

The static modulus of elasticity (E) and the correlation time of rotation ( _c ) of 2,-2,6,6-tetramethylpiperidine-1-oxyl are studied as a function of the temperature (210<T <350°K) for oriented films of isotactic polypropylene and polyethylene of high and low density.E and _c change both upon heating and polymer orientation; this result indicates that sample properties are influenced by the microstructure of the amorphous phase where probes are localized.     

2-Silalactones

Several methods have been developed for the synthesis of 2-silalactones in which the silicon atom is bound to an oxygen atom. Some chemical reactions of these compounds have been studied.     

Die mikrophotometrische bestimmung von kobalt im blutserum und anderen biologischen substanzen

A photometric method is proposed for the determination of cobalt in the form the nitroso-R-salt complex in 5–10 nil of blood serum. The organic matter is destroyed by mineral acids. Iron and copper are separated by oxine and dithizone; they can be determined later. Cobalt (just like traces of other elements), complexed by diethyldithiocarbamate and oxine, is extracted by chloroform and then determined in, the form of the nitroso-R-salt complex. The photometric measurement is carried out in a capillary cuvette 10 cm long and 0.7 ml volume, using a green Literatur S. 561. filter. Amounts of 0.02–0.3 g cobalt can be determined quantitatively, with an accuracy of ±5%.