Ipso attack in the nitration of 5-bromo- and 5-methyl-2-cyclopropylthiophenes

It was established that 5-bromo-2-cyclopropylthiophene and 5-methyl-2-cyclo-propylthiophene undergo transformations during nitration with nitric acid in acetic anhydride that are a consequence of ipso attack of the nitryl cation in the 2 or 5 positions of the thiophene rings of the starting compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 189–194, February, 1981.     

Calculations of silicooxygen ring vibration frequencies

In the work model calculations of the vibrations of ideally isolated silicooxygen rings (using PM3 method) have been carried out. three-, four-, and six-membered rings have been considered. It has been found that that the three-membered silicooxygen rings are flat and practically undeformed showing D_3h symmetry. The rings of higher number of ring members (i.e. n>3) are deformed to some extent. The deformation reveals itself most significantly in the Si–O–Si bond angles distribution. In the case of all the rings the bridging Si–O–Si bonds are ca. 0.02–0.04 Å shorter than the non-bridging Si–O⁻ bonds. Hypothetical IR spectra for all the rings considered have been also calculated. Analysis of these hypothetical spectra leads to the conclusion that the whole spectrum can be divided into four wavenumbers regions, 1200–1100 cm⁻¹ stretching Si–O(Si) vibrations; 1000–800 cm⁻¹ stretching Si–O⁻ vibrations; 800–600 cm⁻¹; the region in which a band characteristic of silicooxygen rings appears, and below 600 cm⁻¹ bending ⁻O–Si–O⁻ and (Si)O–Si–O(Si). It has been also found that as the number of ring members increases the ‘ring band’ shifts to lower wavenumbers: 725 cm⁻¹ for three-membered rings, 650 cm⁻¹ for four-membered rings and 610 cm⁻¹ for six-membered rings. Calculated spectra have been compared with the experimental spectra of cyclosilicates. They showed good agreement in the 1200–600 cm⁻¹ region. In the experimental spectra as well as in the calculated ones, with increasing the number of ring members the ‘ring band’ shifts towards lower wavenumbers.     

Bis(indolyl-3-)phthalides and their spectral properties

Symmetrical bis-indolylphthalides, having electron-releasing and electron-withdrawing substituents on the indole rings, were obtained from the reaction between an indole and an unsubstituted or substituted phthalic anhydride. Unsymmetrical indolylphthalides were synthesized by the condensation of 3-(o-carboxybenzoyl)indole with a substituted indole. A relationship was found to exist between the nature of the substituent, and the spectral and acid-base properties of the compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 915–918, July, 1989.     

Absorption and luminescence spectra of zinc mesotetraphenyl-2,3-tetraphenanthrenoporphin

The electronic absorption and luminescence spectra are affected by the extension of the conjugated system in a tetrapyrrole macroring on account of aromatic-ring annelation, which has been examined for mesotetraphenyl-2,3-tetraphenanthrenoporphin and the zinc complex of it. Fluorescence and phosphorescence characteristics have been measured. The phenanthrene-nucleus annelation to the porphyrin macroring affects the features of the S₁ and T₁ lowest excited states in the same way as the attachment of naphthalene rings in positions 2 and 3 to the latter.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 1, pp. 92–97, January–February, 1990.     

Silica Matrix with anhydride groups for immobilization of enzymes

We have studied the process of preparing a silica support with anhydride groups. The process includes introducing vinyl groups onto the surface with subsequent radiative copolymerization of maleic anhydride with them. The maximum degree of grafting of the functional groups of the matrix occurs for -irradiation doses of 20–30 Mrad. The carboxyl groups grafted to the aerosil surface, formed upon hydrolysis of the support, can be converted to anhydride by calcination at 403 K for 3 h.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 750–753, November–December, 1989.     

Determination of the bond-angle distribution in vitreous B2O3 by B double rotation (DOR) NMR spectroscopy

The B–O–B bond angle distributions for both ring and non-ring boron sites in vitreous B₂O₃ have been determined by ¹¹B double rotation (DOR) NMR and multiple-quantum (MQ) DOR NMR. The [B₃O₆] boroxol rings are observed to have a mean internal B–O–B angle of 120.0±0.7° with a small standard deviation, σ_R=3.2±0.4°, indicating that the rings are near-perfect planar, hexagonal structures. The rings are linked predominantly by non-ring [BO₃] units, which share oxygens with the boroxol ring, with a mean B_ring–O–B_non-ring angle of 135.1±0.6° and σ_NR=6.7±0.4°. In addition, the fraction of boron atoms, f, which reside in the boroxol rings has been measured for this sample as f=0.73±0.01.     

Study of the reactivity of subtituted phthalic acids and anhydrides in condensation reactions with N-carboxymethylpyridinium salts and the synthesis of novel N-(1H-indene-1,3(2H)-dion-2-Yl)pyridinium betaines

Reaction of substituted phthalic acids or their anhydrides (including pyromellitic dianhydride) with salts of N-carboxymethylpyridinium and substituted N-carboxymethylpyridinium in the presence of acetic anhydride and triethylamine in acetonitrile or acetic acid solutions gave a series of novel N-(1H-indene-1,3(2H)-dion-2-yl)pyridinium betaines. Electron acceptors substitutents in the phthaloyl and pyridine rings were found to increase and electron donor substituents-to decrease the reactivity.Riga Technical University, Riga LV-1048, LatviaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12. pp. 1647–1654, December, 1999.     

Selective oxidation using catalyst electrodes supported on solid electrolyte

The major oxygenated products of the selective oxidation of 1-butene by using a catalyst electrode were maleic anhydride on V₂O₅/YSZ/Ag and butadiene on MoO₃–Bi₂O₃–Ag/YSZ/Ag. Their selectivities were enhanced as compared with the non-electrochemical system.     

Synthesis and properties of heterocyclic carbonium systems

Bis(4,4,5,5-tetramethyl-2-dioxolano) trimethylidynecyanine was synthesized by condensation of 2-methyl-1,3-dioxolanium perchlorate with 2-formylmethylene-1, 3-dioxolane by heating (90–100C) in acetic anhydride. It is shown that the 1,3-dioxolane also condenses under similar conditions with pyrylium salts containing active methylene and methyl groups to give unsymmetrical dioxolanopyrylocyanines. The synthesized cyanines react with HClO₄ to give unstable diperchlorates, which readily lose a molecule of HClO₄ to give the starting cyanines. Concentrated HCl decomposes one of the dioxolane rings of the symmetrical cyanine, and refluxing with dilute HCl brings about its destruction to low-molecular-weight unidentified compounds. The unsymmetrical cyanine from the pyrylium salt is resistant to the action of acids but is hydrolyzed by alkalis with cleavage of the pyrylium ring to a diketone. The action of Br₂ on the dioxolanocyanine leads to the addition of bromine to the double bonds and replacement of the ClO₄ ^– ion by Br^–.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 595–598, May, 1977.     

Modification of sturgeon protamines with succinic anhydride

The modification of the - and -NH₂ groups of sturins A and B — protamines fromAcipenser güldenstadti — with succinic anhydride has been studied. Succinylation was carried out at 20°C, pH from 7.5 to 10.5, using a 50 to 180-fold excess of succinic anhydride. The modification products were separated by reversed-phase HPLC on a Zorbax ODS column. A linear relationship has been established between the retention times of the succinyl derivatives and the number of succinyl groups introduced. The influence of the pH and of the excess of succinic anhydride on the modification of the sturins has been studied by the method of experimental planning and mathematical modeling. The optimum conditions have been found for the succinylation of the proteins: a 150- to 180-fold excess of succinic anhydride and pH values of 9.8–10.2 for sturin A and of 8.4–9.4 for sturin B.Moscow Technological Institute of the Meat and Dairy Industry. All-Union Scientific-Research Institute for the Search for New Antibiotics, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 238–243, March–April, 1989.     

Conversions of 2-thioxo-1,3-dithiol-4,5-dicarboxylic acid dimethyl ester — The path to a new heterocyclic system, (4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2,5,7-trione and 5,6-dimercaptouracil derivatives

The conversions of 2-thioxo-1,3-dithiol-4,5-dicarboxylic acid methyl ester into anhydride, mono- and diamide, and monoamide methyl ester were demonstrated. The new heterocyclic system, (4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2,5,7-trione, was obtained by oxidative rearrangement-cyclization of 2-oxo-1,3-dithiol-4,5-dicarboxylic acid diamide with phenyliodosyl(hydroxy)tosylate and used to synthesize previously unknown 5,6-dimercaptouracil derivatives, including nickel dithiolene complex.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1275, September, 1992.     

Crystal and molecular structure of salvicin — A diterpenoid acid of the clerodane series

The spatial structure of the diterpenoid salvicin has been determined by x-ray structural analysis. The trans-linkage of rings A/B proposed previously has been confirmed. This indicates that rings A and B in related diterpenoids — salvin and salvinin — also have the trans-linkage.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 63–68, January–February, 1988.     

Synthesis,electronic structure,and physicochemical characteristics of pyrazolo[1,2-a]pyridazinium

The interaction of 1-methallylpyrazoles with acetic or propionic anhydride in the presence of perchloric acid forms products of acylation at the double bond and subsequent heterocyclization — pyrazolo[1,2-a]pyridazinium salts — that are representatives of a new heteroaromatic system. Analogous cyclization is observed in the acylation of 3-(2-hydroxy-2-methylpropyl-pyrazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1623–1631, December, 1990.     

Reactions of lycoctonine alkaloids with acetic anhydride and p-toluenesulfonic acid

The reactions of alkaloids having a 7,8-diol system — lycoctonine, browniine, and dihydromonticoline — with acetic anhydride and p-toluenesulfonic acid have been studied. The optimum conditions for this reaction, leading to anhydro compounds, have been found.Abuali ibn Sino [Avicenna] Tadzhik State Medical Institute, Dushanbe; Institute of Chemistry, Baskir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 545–547, July–August, 1991.     

Synthesis of vinylsulfonyl(halo)pyridines and their reactions with binucleophilic reagents

Oxidation of vinylthio(halo)pyridines with 30–33% hydrogen peroxide solution in acetic anhydride at 20–25°C furnished vinylsulfonyl(halo)pyridines. Nucleophilic addition reactions of 2-amino-1-ethanethio hydrochloride and thiosemicarbazide to the multiple bonds of vinylsulfonyl(halo)pyridines were performed.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1705–1708.Original Russian Text Copyright © 2004 by Amosova, Gavrilova.     

Synthesis of diquinone derivatives of deuteroporphyrin ix for the study of the first stage in the process of photosynthesis

Diquinone derivatives of deuteroporphyrin IX containing covalent bridges of different lengths between the chromophores have been synthesized. The compounds were prepared by the condensation of hydroxy-quinones with deuteroporphyrin IX using a mixed anhydride method which employed the system di-tert-butyl pyrocarbonate — 4-dimethylaminopyridine. A spectral study of the resulting porphyrin-quinones was carried out.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 176–182, February, 1992.     

Acetylation of lagochilin

The acetylation of lagochilin and its derivatives with acetic anhydride in the presence of pyridine has been studied by PMR spectroscopy. It has been shown that the manifestation of the polyfunctionality of lagochilin in acetylation reactions with acetic anhydride is connected with a change in the nature of the process of solvation of the reaction forms with the subsequent replacement of the hydrogen atoms of the hydroxy groups by acetyl groups.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 46–49, January–February, 1980.     

Study of the products of the reaction of succinic anhydride derivatives with urea

Conclusions The product of the reaction of isododecenylsuccinic anhydride with urea at 120–160°C is isododecenylsuccinimide.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1900–1902, August, 1988.     

Electrophilic 1,5-addition of acyl chlorides to the azocyclopropane system of spiro(1-pyrazoline-3,1′-cyclopropanes)

1-Pyrazolines1–4, which contain a spiro cyclopropane fragment at the adjacent azo group, react selectively with acetyl (benzoyl) chloride or acetic anhydride in the presence of AlCl₃ to give high yields of the corresponding 1-acyl-3-(2-chloroethyl)-2-pyrazolines5–8, adducts of electrophilic 1,5-addition of acyl chlorides to the conjugated azocyclopropane system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1993–1996, November, 1994.This study was financially supported by the Russian Foundation for Basic Research (grant No. 94-03-08902).