Basicity of 3,6-diphenyl-1,2,4,5-tetrazine

We have determined the basicity of 3,6-diphenyl-1,2,4,5-tetrazine in aqueous solutions of sulfuric acid (pK_BH+ is –4.8). According to quantum chemical calculations done by the MNDO method and theab initio method in a 6-31G++ basis, the tetrazine ring is a nonpolar, highly aromatic system similar to benzene. The aromaticity of the tetrazine hererocycle decreases significantly upon protonation, which considerably destabilizes the protonated form.St. Petersburg State Technological Institute, St. Petersburg 198013, Russia, Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 34, No. 1, pp. 120–123, January, 1998.     

Reaction of 5-hydroxy-3,3,5-trimethylisoxazolidine with acrylic acid esters

The reaction of 5-hydroxy-3,3,5-trimethylisoxazolidine with methyl, ethyl, and tert-butyl acrylates, proceeds as Michael addition, and produces previously, unknown 5-hydroxy-3,3,5-trimethylisoxazolidine-2-propionic acid esters. The structures of the obtained products are proved by¹H and¹³C NMR spectroscopy and by their subsequent transformation into 5-hydroxy-3,3,5-trimethylisoxazolidine-2-propionic acid.Institute of High-Molecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, Russia; St. Petersburg State University, St. Petersburg 198904, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 945–947, July, 1999.     

Adamantylazoles: X. Reactions of 1,2,4-Triazole-3-thione with 1-Adamantanol in Acid Solutions

1,2,4-Triazole-3-thione reacts with 1-adamantanol in concentrated sulfuric acid to form 1-(1-adamantyl)-1,2,4-triazole-3-thione, which transforms into 1-(1-adamantyl)-3-(1-adamantyl)sulfanyl-1,2,4-triazole or is oxidized with atmospheric oxygen dissolved in sulfuric acid into 3,3′-disulfanediylbis[1-(1-adamantyl)- 1,2,4-triazole]. 3-(1-Adamantyl)sulfanyl-1,2,4-triazole was prepared by adamantylation of 1,2,4-triazole-3-thione in a mixture of phosphoric and acetic acid (weight ratio 4 : 1).     

Adamantylazoles: XIII. Specificity of acid-catalyzed alkylation of 1-(1-adamantyl)-4,5-dihydro-1H-tetrazole-5-thione

Russian Journal of General Chemistry - In the reaction of 1-(1-adamantyl)-4,5-dihydro-1H-tetrazole-5-thione with 1-adamantyl in sulfuric acid 2-(1-adamantyl)-5-(1-adamantylsulfanyl)-2H-tetrazole...     

Adamantylazoles: XII. Alkylation of 1-R-tetrazole-5-thiones and 1-R-tetrazol-5-ones with tertiary alcohols in sulfuric acid

In the reaction of 1-(1-adamantyl)-4,5-dihydro-1H-tetrazole-5-thione with 1-adamantyl in sulfuric acid 2-(1-adamantyl)-5-(1-adamantylsulfanyl)-2H-tetrazole and 1,3-bis(1-adamantyl)-5-(1-adamantylsulfanyl)-1H-tetrazolium salt are formed. Methylation of 1-(1-adamantyl)-4,5-dihydro-1H-tetrazole-5-thione in alkaline medium affords 1-(1-adamantyl)-5-methylsulfanyl-1H-tetrazole while its interaction with formaldehyde affoeds 1-(1-adamanttl)-4-(hydroxymethyl)-4,5-dihydro-1H-tetrazole-5-thione.     

Adamantylazoles: IX. Acid-catalyzed Adamantylation of 1,2,4-Triazol-3-thione

1,2,4-Triazole-3-thione reacts with 1-adamantanol in sulfuric acid to form 1-(1-adamantyl)-3- [(1-adamantyl)sulfanyl]-1,2,4-triazole and 3,3′-disulfandiylbis[1-(1-adamantyl)-1,2,4-triazole].__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 142–145.Original Russian Text Copyright © 2005 by Amandurdyev, Saraev, Polyakova, Golod.     

Adamantylazoles: XI. Reaction of 1-phenyltetrazole-5-thione with adamantan-1-ol in strong acids

The reaction of 1-phenyltetrazole-5-thione with adamantan-1-ol in sulfuric acid gave 3-(1-adamantyl)-1-phenyltetrazole-5-thione having a mesoionic structure, 5-(1-adamantylsulfanyl)-1-phenyltetrazole, and 3-(1-adamantyl)-5-(1-adamantylsulfanyl)-1-phenyltetrazolium hydrogen sulfate. Hydrolysis of 5-(1-adamantylsulfanyl)-1-phenyltetrazole led to the formation of 1-phenyltetrazol-5-one. The adamantylation process is reversible.     

Methods for the synthesis of mono- and polynuclear NH-tetrazoles. (Review)

Data on methods for the synthesis of monocyclic and polynuclear NH-unsubstituted tetrazoles are reviewed.Dedicated to Prof. H. Elguero on the occasion of his 65th birthday.St. Petersburg State Technological Institute (Technical University), St. Petersburg 198013, Russia; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–884, July, 2000.     

Ring-ring tautomerism in 1,3-alkanoylhydrazonoximes of acetylacetone

The coexistence in solution of tautomeric isoxazoline and pyrazoline forms of 1,3-alkanoylhydrazonoximes of acetylacetone has been detected and investigated by¹H and¹³C NMR spectroscopic methods. The compounds indicated eliminate hydroxylamine under the action of acid catalysts, forming 1-acyl-3,5-dimethylpyrazoles.Institute of High Molecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, RussiaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–829, June, 2000.     

Adamantylation of 3-Nitro- and 3-Ethoxycarbonyl-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-ones

Reaction of 3-nitro- and 3-ethoxycarbonyl-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-ones with 1-adamantanol (or 1-adamantyl nitrate) in concentrated sulfuric acid or with 1-bromoadamantane in sulfolane affords N-adamantyl derivatives. The adamantylation of 3-nitro-1,4-dihydro-7H-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-one yields a mixture of N⁸- and N¹-isomers that undergo interconversion in concentrated sulfuric acid along intermolecular mechanism.     

Synthesis and study of the biological activity of fragments of salmon calcitonin II

A number of fragments of salmon calcitonin II possessing analgesic activity of the nonopioid type have been synthesized.Institute of High-Molecular-Mass Compounds, Russian Academy of Sciences. Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 126–132, January–February, 1993.     

Composition and structure of the novel complex Rh(CO)·(Ph2PNH2)3

Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Institute of Applied Chemistry, St. Petersburg. Kazan Chemical Engineering Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 6, pp. 140–145, November–December, 1992.     

Synthesis of ethers and esters of 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoxalm under conditions of interfacial catalysis

Esters and ethers of the 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoyaline have been obtained under conditions of interfacial catalysis in a chloroform-water system. The catalytic activities of tetrabutylammonium bromide and cetyltriethylammonium bromide have been compared in the synthesis of the acetate, benzoate, and 4-nitrobenzoate of the 1,4-di-N-oxide of 2,3-bis(hydroxymethyl)quinoxaline.St. Petersburg State Technological Institute, St. Petersburg 198013. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–820, June, 1994. Original article submitted June 29, 1994.     

Structural analogy principle for estimating gas chromatographic retention indices

It is shown that using additive schemes complying with the general principle of structural analogy for all molecular transformations is admissible for calculating gas chromatographic retention indices, which are very important analytical parameters for identification of organic compounds. From this viewpoint, we compare the possibilities of using the homomorphism factors and the fit increments of the retention indices of reagents and products in chemical reactions, including those of some topochemically equivalent hypothetical transformations of the structure and composition of organic molecules. Scientific-Research Institute of Chemistry, St. Petersburg University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 4, pp. 784–795, July–August, 1996. Translated by L. Smolina     

Transformations of 2-(3-Hydroxy-3-methyl-1-butynyl)adamantan-2-ol >Catalyzed by Acids

Reaction of 2-(3-hydroxy-3-methyl-1-butynyl)adamantan-2-ol with acetonitrile under Ritter reaction conditions is accompanied by isomerization and partial hydration where the water addition to the triple bond occurs nonselectively. As a result of reaction carried out in the presence of 8 equiv of sulfuric acid a mixture was obtained of N ²-[4-(1-acetylamino-2-adamantyl)-2-methyl-3-butyn-2-yl]acetamide, N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-2-oxo-3-butyl]-acetamide, and N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-1-oxo-3-butyl]acetamide in ~10:3:2 ratio. In the presence of 2 equiv of the acid the mixture obtained consisted of N ²-[4-(1-acetylamino-2-adamantyl)-2-methyl-3-butyn-2-yl]acetamide, N ³-[1-(1-acetylamino-2-adamantyl)-3-methyl-2-oxo-3-butyl]acetamide, and 1-(1-acetylamino-2-adamantyl)-3-methyl-2-buten-1-one in the same ratio. In Rupe reaction conditions we obtained instead of the expected ,-unsaturated ketones a mixture of 1-(1-hydroxy-2-adamantyl)-3-hydroxy-3-methylbutan-1-one and 1-(1-hydroxy-2-adamantyl)-3-hydroxy-3-methylbutan-2-one in a 5:3 ratio.     

Synthesis and investigation of the antitumoral activity of shortened analogs of luliberin

With the aim of obtaining antitumoral drugs possessing a binary action mechanism, we have synthesized a series of shortened analogs of luliberin, including some containing a 1-carboxymethyl-5-fluorouracil residue. Their antitumoral and hormonal activities have been investigated.Institute of High-Molecular-Mass Compounds, Russian Academy of Sciences, St. Petersburg. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 655–662, September–October, 1994.     

Branched polycyclic tetrazole systems. 1. Synthesis and structure of 2-(5-tetrazolyl)ethyl derivatives of some CH-, OH-, and NH-acids

The cycloaddition of dimethylammonium azide to the nitrile groups of 2-cyanoethyl derivatives of CH-, OH-, and NH-acids leads to open-chain branched structures containing terminal NH-tetrazolyl groups. An x-ray diffraction structural analysis of tris[2-(5-tetrazolyl)ethyl]nitromethane revealed steric access of the equivalent NH-tetrazolyl rings of the branched system. In going from the branched nitrile substrates to the corresponding tetrazoles, the PMR spectra show a breakdown in the resolution of the multiplet components, which had not been observed previously for monocyclic 5-substituted tetrazoles. A dependence was found for the¹³C NMR chemical shifts on the pK_a values, reflecting the NH-acidity of the branched polycyclic tetrazoles in water. Dedicated to the memory of I. N. Goncharova. St. Petersburg State Technological Institute, 198013 St. Petersburg. V. A. éngel'gart Institute of Molecular Biology, Russian Academy of Sciences, 117984 Moscow. L. Ya. Karpov Physics and Chemistry Research Institute, 103062 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1494–1501, November, 1997.     

Investigation of the role of the pyrimidine ring in the main chain of polyamido acids and polyimides. 2. Characteristics of the thermocyclization of polypyromellitamido acids based on 2,5-bis(p-aminophenyl)pyrimidine and 4,4′-diaminoterphenyl

The thermocyclization of polypyromellitamido acids based on 2,5-bis(p-aminophenyl)pyrimidine and 4,4-diaminoterphenyl was investigated by thermogravimetric and mass spectrometric analysis. Characteristics of the thermocyclization of pyrimidine-containing polyamido acids due to the presence of a basic nitrogencontaining ring in the main macrochain were revealed. The hypothesis advanced in Part 1, that the pyrimidine ring displaces solvent molecules bound to the polyamido acid, was confirmed. The hypothesis of the presence of shift packing in a pyrimidine-containing polyamido acid was confirmed by its greater kinetic homogeneity in comparison with the completely aromatic analog.Institute of High-Molecular-Weight Compounds Russian Academy of Sciences, 199004 St. Petersburg. Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2297–2301, October, 1992.     

Polyimides from complexes of benzophenonetetracarboxylic acid diesters with diamines. 5. Mechanism of thermal cyclization of H-complexes

The results of a study, by thermal mass spectrometric analysis and NMR spectroscopy, of the polycondensation of H-complexes are presented from which it is possible to propose a mechanism for the reaction. It is shown that conversion of the H-complexes into polyimides takes place through the formation of intermediate zwitterions with an amino acid bond after initial separation of methanol, following which elimination of water commences in one stage to form an imide ring. The role of theortho position of the functional groups in the acid ester during the formation of the hydrogen bond is discussed.Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2517–2524, November, 1992.     

Synthesis and anticholinesterase activities of quininyl dialkyl phosphates

The results are given of the synthesis of dialkyl phosphate derivatives of the alkaloid quinine and the study of their inhibitory activity in relation to the cholinesterases of various animal species. Institute of Organic Chemistry and Coal Chemistry, National Academy of Sciences, Republic of Kazakhstan, Karaganda. I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 411–414, May–June, 1994.