Importance de la conformation des complexes XC6H5Cr(CO)3 pour la regiosélectivité d'additions nucleophiles sur le cycle aromatique

The site of preferred nucleophilic attack on XC₆H₅Cr(CO)₃ complexes is more influenced by the conformation of the Cr(CO)₃ group than by the nature of X substituent. This is supported both by experimental and theoretical results.     

Synthesis of 3-epistrophanthidin and 3-epistrophanthidol

Chemistry of Natural Compounds - 3-Epistrophanthidin and 3-epistrophanthidol have been synthesized from strophanthidin and strophanthidol with yields of 10 and 40%, respectively. The substances...     

Preparation of 1,2,3,4,7,7-Hexachlörobicyclo[2.2.1] hepta-2,5-diene by condensation of Hexachlorocyclopentadiene with acetylene

Summary 1,2,3,4,7,7-Hexachlorobicyclo[2.2.1] hepta2, 5- diene, a starting material for the synthesis of the insecticides isodrin and endrin, was prepared by condensation of hexachlorocyclopentadiene with acetylene under pressure.     

Synthesis of New Iron-Containing Carbon Cages by Reaction of C60 Fullerene with Ferrocene

Reaction of C₆₀ fullerene with ferrocene in the presence of aluminum chloride and aluminum in an inert atmosphere gave ferrocenyl-substituted fullerene 2C₆₀ ·1.5(C₅H₅)₂Fe ·3H₂O. The product is a thermally stable iron-containing carbon cage in which the intersphere cavity is formed by three C₆₀ polyhedra and is closed by cyclopentadienyl ligands via formation of four carbon-carbon bonds.     

Gas chromatographic quantitation of underivatized amines in the determination of their octanol-0.1 M sodium hydroxide partition coefficients by the shake-flask method

The elution behaviour of a selection of sequence variant and modified insulins has been compared on a C18 reversed-phase column. Observed elution times were compared with those expected from the nature of the differences from bovine insulin. In some cases prediction rules established for peptides are adequate to explain the observed elution and in others detailed knowledge of the structure of the protein is of considerable importance in understanding elution behaviour.     

Five-membered-ring-substituted 1-methyl-1H-indeno[1,2-b]pyridines

1-Methyl-1H-indeno[1,2-b]pyridine and 1-methyl-1H-5-(, -dicarbomethoxyvinyl)-(formyl, acetyl)indeno[3,2-b]pyridines were obtained by treatment of N-methyl-4-azafluorenium iodide, as well as mixtures of it with acetylenedicarboxylic ester, dimethylformamide (DMF), and phosphorus oxychloride or acetic anhydride, with bases. 4-Azafluoronenone was used to synthesize 9-(p-methoxyphenyl)-4-azafluoren-9-ol, which was reduced to 9-(p-methoxyphenyl)-4-azafluorene, and 1-methyl-1H-5-(p-methoxyphenyl)indeno[3,2-b]pyridine was obtained from the methiodide of the latter.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1382–1386, October, 1981.     

The determination of traces of ammonium-nitrogen in aqueous solution by optical emission spectrometry with a high-frequency inductively coupled argon plasma source

A method for the determination of low levels of ammonium ion in solution by optical emission spectrometry with an inductively coupled argon plasma source operated at 27 MHz is presented. The ammonium ion is oxidized with sodium hypobromite in alkaline medium, the evolved nitrogen is passed into the argon plasma, and the NH emission intensity produced in the plasma at 336.0 nm is monitored. A practical detection limit of 0.1 μg N ml^-1 for 5-ml aqueous sample solutions has been obtained. The method has been applied to the determination of the exchangeable ammonium content of soil samples.     

New approach to the synthesis of 3-amino-1,2-benzothiazine 1,1-dioxides

The possibility of obtaining 3-amino-1,2-benzothiazine 1,1-dioxides by nucleophilic substitution of the chlorine atom in 5-nitro-2-chlorobenzenesulfonamides by carbanions generated from substituted acetonitriles was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 264–266, February, 1992.