Phase relationships in the system Y2O3-ZrO2

Russian Chemical Bulletin -     

Investigation of the structure of 1,2-dihydro-3-(2-hydroxyphenyl)-4-nitropyrazol-5(3H)-one by spectroscopic and quantum-chemical methods

The structure of the previously synthesized 1,2-dihydro-3-(2-hydroxyphenyl)-4-nitropyrazol-5(3H)-one (I) was studied by ¹H and ¹³C NMR, IR, and electronic spectra. It was established that the NMR spectra of compound (I) do not contain signals for the H atom at position 4 and the C atoms of the carbonyl groups; in the crystalline state and in solutions the IR spectra do not contain v_c=o bands, while the electronic spectra do not contain absorption in the region of 250 nm. On the basis of the foregoing it is concluded that compound (I) exists in the OH form. The distribution of -electron density in the molecule of (I) and the nature of the bands in its electronic absorption spectrum were studied by quantum-chemical methods in the PPP approximation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1510–1516, November, 1990.     

Spectroscopic study of 1-cyanoacetyl-2-alkylhydrazines and their ring isomers — 1-alkyl-5-amino-3-pyrazolones

The structures of 1-cyanoacetyl-2-alkylhydrazines and their ring isomers, viz., 1-alkyl-5-amino-3-pyrazolones, to which they are readily cyclized, were investigated by IR, UV, and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 516–519, April, 1981.     

Photoproduction of homogeneous chromium(V) compounds in pentanol for targets containing polarized hydrogen nuclei

Measurements have been made on photochemical and subsequent dark reactions with an He-Cd laser (44l nm) with ammonium dichromate solutions in pentanol. Exposing the solution directly in the spectrometer cavity leads to an ESR signal having g = 1.973 characteristic of chromium(V) compounds. The compounds have been examined by ESR and optical spectroscopy. A kinetic analysis is presented. It is suggested that homogeneous Cr(V) compounds are formed. No Cr(III) or other paramagnetic products have been detected. These compounds can be used in polarized nuclear targets.Joint Nuclear Research Institute, Dubna. Pisarzhevskii Physical Chemistry Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Teoreticheskaya i Éksperimental' naya Khimiya, No. 1, pp. 60–65, January–February, 1991. original article submitted November 17, 1987.     

Synthesis of 3-cyano-4, 6-diaryl-3, 4-dihydropyridine-2-thionks

3-Cyano-4, 6-diaryl-3, 4-dihydropyridine-2-thiones have been synthesized for the first time by the condensation of arylideneacetophenones or 1-piperidino-1-phenyl-2-benzoylethane with cyanothioacetamide and the 1, 1-dicyano-2-aryl-3-benzoylpropane with hydrogen sulfide in the presence of bases. It has been established by PMR spectroscopy that 3-cyano-3,4-dihydropyridine-2-thiones exist in solutions in the form of mixture of cis and trans isomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1515–1520, November, 1983.     

Reactions of heterocyclic cations with nitrogen-containing nucleophiles. 10. Synthesis of 3,5,7-triaryl-1,2-oxazepinium perchlorates by the reaction of 2,4,6-triarylpyrylium salts with nitrones and substituted hydroxylamines

2-Substituted 3,5,7-triaryl-1,2-oxazepinium perchlorates were obtained by the reaction of 2,4,6-triarylpyrylium salts in dimethylformamide with nitrones and N-arylhydroxylamines. The products are the first representatives of seven-membered cations with eight electrons.See [1] for Communication 9.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 457–460, April, 1982.     

Heterocyclic bioantioxidants. 2. Interaction of 3-nitro-4-substituted coumarins with mercaptans

3-Nitro-4-chlorocoumarin forms 3-nitro-4-substituted coumarins when it reacts with an equimolar quantity of benzyl mercaptan or thiosalicylic acid; with excess benzyl mercaptan, it forms 3,4-di-S-benzyl coumarin. 3-Nitro-4-methoxycoumarin under the same conditions, with an equimolar ratio of reagents, forms a mixture of monosubstituted and disubstituted products. A mechanism is proposed for these reactions.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1476–1479, November, 1991.     

Synthesis and study of the light-stabilizing activity of some dithiocarbamates that include a heteroaromatic ring

A number of new dithiocarbamates of transition metals that contain thiophene, furan, benzo[b]thiophene, and benzo[b]selenophene rings were synthesized. The compounds obtained were investigated as light stabilizers for polymers. It is shown that the effectiveness of the light-stabilizing effect of the dithiocarbamate depends on the structure of the heterocyclic fragment included in its composition.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1482–1488, November, 1982.     

Ring cleavage and ring expansion of indoles by superoxide ion

The reaction of indoles ($\text{1}$) with superoxide ion resulted in ring cleavage to give $\text{o}$-formyl and $\text{o}$-acylaminoketones ($\text{6}$) or N-acylanthranilic acid ($\text{8}$) and ring expansion yielding 2-quinolones ($\text{7}$). All reactions are chemiluminescent except that of 2-methylindole ($\text{lh}$), which gave a coupled product ($\text{9}$).     

Synthesis of N-benzyloxycarbonyl-N-methylaminoacids from oxazolidine-5-one derivatives

Hydrogenolysis of 3-benzyloxycarbonyloxazolidine-5-one and 3-benzyloxycarbonyl-4-benzyloxazolidine-5-one by Et₃SiH in the presence of F₃.CCO₂H is demonstrated to be a convenient method for preparing substituted N-methylaminoacids. In contrast with catalytic hydrogenation on Pd/C catalyst, the benzyloxycarbonyl is not removed and the methyl is not lost using this method.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–683, May, 1992.