The mechanism of oxidation of indoxyl and its analogs to indigo and indigoides

Conclusions Intermediate formation of 3-oxynaphthenyl-2 radical during oxidation of 3-oxythionaphthene to thioindigo was demonstrated by the inhibitor method. The 1:1 recombination product of this radical and diphenylpicrylhydrazyl was isolated. It is assumed that the postulated oxidation mechanism is general for compounds possessing a methylene group bonded to an electron-donating X group and an electron-accepting C=O group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1168–1170, May, 1970.     

Structure,tautomerism, and transformations of β-(3-nitro-2-pyridyl)- and β-(3-nitro-4-pyridyl)pyruvic acid esters

It was shown by means of IR, UV, and PMR spectra that -(3-nitro-2-pyridyl)pyruvic acid esters are practically completely enolized in the crystal state and in solution; ethyl -(3-nitro-4-pyridyl)pyruvate has an enol structure in the crystalline state and in pyridine solution but exists as a mixture of keto and enol forms in low-polarity solvents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–393, March, 1974.     

Silicon-29 diffusion-ordered NMR spectroscopy (DOSY) as a tool for studying aqueous silicates

The first use of silicon-29 diffusion-ordered NMR spectroscopy (DOSY) is reported, in a study of the speciation of aqueous silicates.     

Synthesis,alkylation, and molecular and crystal structure ofN-methylmorpholinium 6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocyclohexane-2-thiolate

The reaction of cyano(cyclohexylidene)thioacetamide with cyanothioacetamide or malononitrile andN-methylmorpholine yieldsN-methylmorpholinium 6-amino-3,5-dicyano-1,4-dihydropyridine-4-spirocyclohexane-2-thiolate. Its structure was established based on the results of alkylation and X-ray structural analysis.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2535–2540, October, 1996.     

Properties of Monocarboxy Cellulose Containing Sorbed Fe(III), Al(III), and Cr(III) Cations

Sorption of Fe(III), Al(III), and Cr(III) on monocarboxy cellulose at various pH, concentrations of metal chloride or sulfate in solution, and time was studied. The effect of type and amount of the cation sorbed on the physicomechanical properties, swelling, and stability in phosphate buffer of monocarboxy cellulose fibers was considered.     

Pyrazolines — Derivatives of 2-nitrochalcone

By the reaction of 2-nitrochalcone with hydrazine hydrate, 5-(2-nitrophenyl)-3-phenyl-1H-2-pyrazoline (I) and the hydrazone of 3-(5-(2-nitrophenyl)-3-phenyl-2-pyrazolin-1-yl)-3-(2-nitrophenyl)propiophenol (II) have been prepared. The acylation of both compounds I and II leads to N-acyl derivatives of the first. The acylating ability of formamide and N,N-dimethylformamide was observed in reactions with pyrazoline I. An x-ray structural study was carried out on compound II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 360–366, March, 1993.     

Ecdysteroids of a culture of tissues and cells ofAjuga turkestanica

The possibility has been studied of obtaining ecdysteroids — ecdysterone and turkesterone — with the aid of a culture of the tissues and cells of the plantAjuga turkestanica. Conditions have been selected under which the yield of ecdysteroids in the culture of tissues and cells is comparable with amounts of the same substances in the organs of the whole plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 51–52, January–February, 1990.     

Mesoionic compounds with a bridge nitrogen atom. 19. Thiazolo[3,2-a]quinoxalinium oxides

(2-Quinoxalylthio)acetic acids have been found to cyclize on treatment with acetic anhydride to give the mesoionic thiazolo[3,2-a]quinoxalinium oxides. Some reactions of these compounds have been studied, and the relationship of the color of the compounds to their chemical structure examined.For Communication 18, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1680–1684, December, 1989.