Synthesis of polyfunctionally substituted benzothiazines based on vinylthionahlobenzenes and 2-mercaptoethylamine

Regioselective nucleophilic substitution of the fluorine atoms in positions 2 and 5 of the benzene ring takes place in the reaction of 3,6-bis(vinylthio)-1,2,4,5-tetrafluoro- and 3-vinylthio-6-chloro-1,2,4,5-tetrafluorobenzenes with 2-mercaptoethylamine in isopropyl alcohol-water-dimethylformamide mixture at 40–45°C in the presence of KOH. The products of disubstitution obtained are converted into 1,4-benzothiazines on heating to 100°C in dimethylformamide in the presence of K₂CO₃ as a result of intramolecular substitution.Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk 664033, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 706–709, May, 1998.     

Oxidation of 2-Chloro-1-phenylethane-1,1-dithiol

Oxidation of 2-chloro-1-phenylethane-1,1-dithiol with bromine, iodine, and elemental sulfur, as well as under UV irradiation, leads to formation of 1,4-bis(chloromethyl)-1,4-diphenyl-2,3,5,6-tetrathiane in 50–95% yield. Oxidation of the same substrate with selenium dioxide gives 1,5-bis(chloromethyl)-1,5-diphenyl-2,4-dithia-3-selenapentane-1,5-dithiol. On heating to 60°C, the latter loses selenium to afford 1,4-bis-(chloromethyl)-1,4-diphenyl-2,3-dithiabutane-1,4-dithiol.     

Synthesis of 1, 2-bis(b-amino-o-carboranyl)ethane and 1,4-bis(b-amino-o-carboranyl)benzene

Conclusions 1,2-Bis(B-amino-o-carboranyl)ethane and 1,4-bis(B-amino-o-carboranyl)benzene were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1669–1670, July, 1976.     

Synthesis and absorption-fluorescence properties of

1,4-Bis(²-pyrazolin-3-yl)benzene derivatives were synthesized by the reaction of dibenzal-p-diacetylbenzene or 1,4-bis(-dimethylaminopropionyl)benzene with various hydrazines. Some of these derivatives were converted to the corresponding 1,4-bis(3-pyrazolyl)benzene derivatives by oxidative dehydrogenation with sulfur. The absorption and fluorescence spectra of the synthesized compounds were measured, and the fluorescence quantum yields were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–83, January, 1980.     

Synthesis of a symmetrical dithiirane

The reaction of p-xylene with epichlorohydrin in the presence of aluminum chloride gave 1,4-dimethyl-2,5-bis(1-chloro-2-hydroxypropyl)benzene, which serves as the starting compound for the synthesis of the corresponding symmetrical dithiirane.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1319–1321, October, 1985.     

Thermal studies on oligosilylbiguanides: A mechanistic approach

Thermal decomposition of oligo-1,4-bis(silyl)-5-propyl/phenylbiguanides, 1–4 under controlled conditions (130–140 °C/N₂) proceeds predominantly via the formation of organic amines, cyclic silazanes and cyclic silylcarbodiimides. Detection of these low molecular weight products accounts for the low residual yields in thermogravimetric analysis of 1–4. A plausible mechanism for thermal degradation is suggested.     

Method for the synthesis of bisbenzo[c]pyrylium salts

A new method for the synthesis of bisbenzo[c]pyrylium salts was developed. The new method is based on the acylation of 1,4-bis(3,4-dimethoxyphenylacetyl)benzene with carboxylic acid anhydrides in the presence of perchloric acid or with carboxylic acids in polyphosphoric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 600–602, May, 1987.     

The Solvent Effect on the Rate of Reaction between Propanethiol and Chlorine Dioxide

The products and kinetics of the liquid-phase oxidation of propanethiol by chlorine dioxide in organic media (n-heptane, 1,4-dioxane, carbon tetrachloride, benzene, diethyl ether, ethyl acetate, acetone, and acetonitrile) at temperatures from –10 to 70°C were examined. The reaction rate constants and activation parameters were measured in the above solvents. A strong solvent effect on the reaction kinetics was found (k= 1.67 × 10^–3or 52.7 l mol^–1s^–1(25°C) in heptane or acetonitrile, respectively). The data were analyzed in terms of the Leydler–Eyring and Koppel–Palm equations. The formation of high-polarity intermediates in the test reaction was suggested.     

Indirect Electrochemical N-Dimethoxyphenylation of 3-Nitro-1,2,4-triazole and Tetrazole

Using the obtaining of 1,4-dimethoxy-2-(3-nitro-1,2,4-triazole-1-yl)benzene (I) and 1,4-dimethoxy-2-(tetrazolyl-1+-2)benzene (II) as an example, a method for indirect electrosynthesis of these substances is developed. In the first stage of this process, electrosynthesis of 1,1,4,4-tetramethoxycyclohexane-2,5-diene is realized by means of oxidation of 1,4-dimethoxybenezene on a platinum anode in an environment of MeOH in a diaphragmless cell. In the second, chemical interaction of this diene with 3-nitro-1,2,4-triazole and tetrazole is performed when heating a mixture of these substances for a long time at 110°C in the presence of additives of collidine. As a result, target products I and II were obtained with a good (60–90%) yield. Realization of this process opens new possibilities for producing N-arylazoles.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 1014–1019.Original Russian Text Copyright © 2005 by Burasov, Vakhotina, Petrosyan.     

Synthesis, spectral luminescent and scintillation properties of organic luminophores based on carbonyl-containing derivatives of 2-(fur-2-yl)-5-phenyloxazole

A series of derivatives of 2-(fur-2-yl)-5-phenyloxazole with various substituents in the 5-position of the furan ring and furan-containing analogs of 1,4-bis(5-phenyloxazol-2-yl)benzene are synthesized. Their spectral-luminescent properties are investigated.Institute of Single Crystals, National Academy of Sciences of Ukraine, Kharkov 310001Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 317–323, March, 1999.     

Reactions of 1,4-bis(tetrazole)benzenes: formation of long chain alkyl halides

The reactions of 1,4-bis[2-(tributylstannyl)tetrazol-5-yl]benzene with α,ω-dibromoalkanes were carried out in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazole. This led to the formation of several alkyl halide derivatives, substituted variously at N1 or N2 on the tetrazole ring. The crystal structures of 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (2-N,2-N′), 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (1-N,2-N′) and 1,4-bis[(2-(8-bromooctyl)tetrazol-5-yl)]benzene (2-N,2-N′) are reported. Further discussion involves the structure of 1,4-bis[2-(6-bromohexyl)-2H-tetrazol-5-yl]benzene (2-N,2-N′) previously reported.     

Formation of mixed aryl–, alkyl–lithium aggregates in the heteroatom assisted lithiation of α,α′-dialkyl substituted 1,3-bis[(dimethylamino)methyl]benzene

The heteroatom assisted lithiation of 1,3-bis[1-(dimethylamino)ethyl]benzene with n-BuLi afforded 2,6-bis[1-(dimethylamino)ethyl]phenyllithium. An X-ray crystal structure determination revealed a dimeric aggregate in which the four benzylic chiral centers are identical, pointing to stereoselective crystallization. In contrast, reaction of 1,3-bis[1-(dimethylamino)propyl]benzene with n-BuLi afforded a dimeric aggregate comprising the parent lithiated compound and n-BuLi in a 1:1 molar ratio. The four Li atoms and the four bridging carbon atoms are arranged in a unique ladder-type C–Li₂–C₂′–Li₂–C framework.     

Method for the synthesis of 1,4-bis(4′-aminophenylthio)-benzene

Conclusions A method was proposed for the six-step synthesis of 1,4-bis(4-aminophenylthio)benzene from 4-nitrochlorobenzene which gives the target product in high purity and overall 13% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2794–2797, December, 1984.     

Electrochemical and spectral properties of thienylene-polyparaphenylenevinylene derivative stereoisomers

Four new compounds: 1,4-dimetoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-dietoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-isopropyloxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene) and 1,4-dietoksy-2,5-bis[2-(5-methylthiophen-2-yl)ethenyl]benzene are synthesized. Three steroisomers ZZ, EZ and EE are isolated from the reaction mixture for the first two of them. Third compound is fully converted to the most stable EE form. Polymerization of all isomers leads to identical polymeric product. Mechanism of polymerization is recognized by using model molecule with methyl substituents blocking α-, α′-sites. All seven stereoisomers have photoluminescent properties. Detailed spectral and electrochemical studies reveal isomerization phenomena during oxidation or at light exposure. Published in Russian in Elektrekhimiya, 2006, Vol. 42, No. 12, pp. 1401–1408. Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes.” October 18–22, 2005, Moscow. The text was submitted by the authors in English.     

Ammonolysis of 1,4-bis(dimethylchlorosilyl)benzene

The ammonolysis of 1,4-bis(dimethylchlorosilyl)benzene with ammonia forms heterocyclic compounds of low molecular weight. The main reaction product is the crystalline [CH₃)₂SiC₆H₄Si(CH₃)₂NH]₄, which polymerizes on heating with the formation of polymers possessing a relative viscosity of 0.15–0.4.     

Synthesis of acetylenic derivatives of 1,4-dioxane

Cyclic ketals — 2,5-dimethyl-2,5-bis(4-penten-2-ynyloxy)-1,4-dioxane and 2,5-dimethyl-2,5-bis(3-phenyl-2-propynyloxy)-1,4-dioxane — were isolated in the reaction of propargyl alcohol with vinyl- and phenylethynylcarbinols in the presence of HgO-BF₃.O(C₂H₅)₂ catalytic system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1029–1030, August, 1986.     

Substitution reactions involving the 2,6-methyl groups of 1,4-dihydropyridines

4,4-Disubstituted 1,4-dihydropyridines (I) are brominated with bromine in chloroform to give 2,6-bis(bromomethyl)-4,4-disubstituted 1,4-dihydropyridines (II), whereas 2,6-bis(dibromomethyl)-4,4-disubstituted 1,4-dihydropyridines (III) are obtained in the case of bromination of I in acetic acid. The bromine atoms in II and III are labile and readily undergo nucleophilic substitution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1519–1524, November, 1978.     

Bis-(N2-hydroxyhexafluoroisopropyl-N1,N1-substituted)terephthalamidines and their reaction with perfluorohexanecarbonitrile

Bis(N²-hydroxyhexafluoroisopropyl-N¹,N¹-substituted) terephthalamidines, which are stable up to their melting points, were obtained by reacting substituted tetraphthalamidines with hexafluoroacetone. The reaction of bis(N²-hydroxyhexafluoroisopropyl-N¹N¹-substituted)terephthalamidines with perfluorohexanecarbonitrile results in the formation of 1,4-bis(2,4-per-fluorohexyltriazinyl) benzene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1613–1616, July, 1990.     

Polyfunctional macroheterocycles

The reaction of 1-[1,2-bis(carbomethoxy)ethyl]aziridine with ethane-1,2-dithiol leads to 1.8-bis[1,2-bis(carbomethoxy)ethylamino]-3,6-dithiaoctane. Condensation with phthalic and terephthalic acid dichloride gives 9,10-benzo-8, 11-dioxo-7,12-bis[1,2-bis(carbomethoxy)ethyl]-1,4-dithia-7,12-diazacyclotetradec-9-ene and 9,12-benzo-8,13-dioxo-7,14-bis[1,2-bis(carbomethoxy)ethyl]-1,4-dithia-7,14-diazacyclohexadeca-9,12-diene, respectively, while condensation with formaldehyde gives 7,9,18,20-tetrakis[1,2-bis(carbomethoxy)ethyl]-1,4,12,15-tetrathia-7,9,18.29-tetraazacyclodocosane. The corresponding disulfone is formed in the oxidation of 9,10-benzo-8,11-dioxo-7,12-bis[1,2-bis(carbomethoxy) ethyl]-1,4-dithia-7,12-diazacyclotetradec-9-ene with 30% hydrogen peroxide.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1563–1565, November, 1988.     

Spectral,luminescent, and photophysical properties of dipyrrolylbenzenes

Dipyrroles with a phenylene bridge, 1,4-bis(pyrrol-2-yl)benzene, 4-(1-vinylpyrrol-2-yl)-1-(pyrrol-2-yl)benzene, and 1,4-bis(1-vinylpyrrol-2-yl)benzene, show intense room-temperature fluorescence in solutions. Analysis of electronic absorption spectra, fluorescence spectra, and results of B3LYP, TD B3LYP, and CIS quantum chemical calculations showed that the introduction of a bulky substituent in position 1 of the pyrrole ring makes the ground-state structures of dipyrrolylbenzenes less planar. Excited-state geometries of all molecules relax to more planar conformations. An increase in the probability of nonradiative transitions has little effect on the quantum yields of fluorescence (Φ_f) of dipyrrolylbenzenes. Even for 1,4-bis(1-vinylpyrrol-2-yl)benzene, where the pyrrole rings deviate from the benzene ring plane by 44°, the fluorescence efficiency remains high enough (Φ_f = 0.7). Substitution at nitrogen atoms has little effect on positions of fluorescence band maxima. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1433–1438, July, 2008.