Synthesis of peptides based onβ-(N1-uracilyl)-α-alanine

The synthesis of peptides which include a DL--(N₁-uracilyl)--alanine (DL-willardiine) residue as an N-terminal or C-terminal group was investigated, dipeptides of DL-willardiine with glycine and L-tyrosine were obtained, and DL-willardiyl-DL-willardiine was synthesized; the latter is the simplest representative of the family of monotonic homopeptides which contain, as a repeating side substituent, a natural nucleic base capable of participation in intermolecular interactions of the complementary type.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–408, March, 1971.     

Alkylation of anionoid intermediates in the reaction of benzofuran with lithium in hexametapol

It is shown that the principal pathway in the reaction of benzofuran with a solution of lithium in hexametapol is opening of the furan ring of benzofuran to give a dilithium derivative. Mono- and dialkylation products are formed when the reaction mixture is treated with alkylating agents. It was established by the use of alkylating agents with different degrees of hardness that the oxygen atom is a softer polarizable center than the sp-hybridized carbanion center.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–23, January, 1978.     

Synthesis and Structure of Some N-[3-(Het)aryl-2-propenylidene]trifluoromethylanilines

The reactions of 4-nitrocinnamaldehyde with trifluoromethylanilines in the presence of molecular sieves were studied, and a series of new aromatic and heterocyclic aldimines were synthesized. The molecular and crystal structure of some of them were determined by X-ray crystallographic analysis.     

Evaluating molecular asymmetry

A method for calculating the asymmetry parameters of molecules based on Avnir’s CSM approach combined with the “dissymmetry function” method is suggested. The performance of the approach is demonstrated on various geometrical models — high-symmetry antiprisms of S₁₀ and D₅ symmetry groups, helices, and molecular objects. It is shown that the MCSM method unambiguously determines the symmetry element or estimates the degree of asymmetry for molecules from different structural classes. A. V. Bogatskii Physiocochemical Institute, Ukrainian Academy of Sciences. Odessa State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 547–552, May–June, 1998.     

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.