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Condensation of 1,2-diaminobenzimidazole with N-arylitaconimides was studied. It was found that 2-(10-amino-N-aryl-2-oxo-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazol-3-yl)acetamides were formed in the course of this reaction upon brief heating to reflux of the reagent mixture in 2-propanol in the presence of catalytic amounts of acetic acid.

We studied the condensation of 1,2-diamino-4-phenylimidazole with N-arylmaleimides and established that this reaction occurred upon brief refluxing of reactants in isopropanol in the presence of a catalytic amount of acetic acid and produced substituted 7-amino-N-aryl-2-oxo-5-phenyl-1,2,3,4-tetrahydroimidazo[1,5-b]pyridazine-4-carboxamides. Performing this reaction at room temperature led to the acyclic intermediates N-aryl-3-(1,2-diamino-4-phenylimidazol-5-yl)pyrrolidine-2,5-diones.

The reactivity of a series of polyfluorinated 2-alkynylanilines with various alcohols using p -TSA has been studied. It was found that hydration of the triple bond gave rise to polyfluorinated 2-aminoarylketones and competed with an electrophilic heterocyclization reaction leading to polyfluorinated indoles. The dependence of the reaction pathways on the nature of the alkynylaniline substituents has been examined.

The title pyridazine derivatives are synthesized through a regioselective intramolecular cyclization mechanism.

A regio- and stereoselective method for preparation of novel functionalized pyrimidine derivatives containing the vinylsulfanyl group has been developed based on addition reactions of 2-thiouracils with phenylethynyl ketones. Reactions with ketones containing the disubstituted triple bond afford adducts of Z-stereochemistry, whereas addition to ketone with the terminal triple bond gives preferentially products of E-configuration.

The reaction of 1,2-diamino-4-phenylimidazole with 5,5-R,R1-cyclohexane-1,3-diones and with the dimethyl formamide dimethyl acetal or triethyl orthoformate gives 7,7-R,R1-3-amino-1-phenyl-7,8-di-hydroimidazo[1,5-b]cinnolin-9(6H)-ones in good yield. These products may also be obtained from 1,2-diamino-4-phenylimidazole and 5,5-R,R1-(phenylaminomethylidene)cyclohexane-1,3-diones.

using the three-component reaction of 1,2-diaminoimidazoles (I) with primary amines and formaldehyde

Oxaselenane derivatives are obtained in reactions of diallyl ether with selenium dichloride and dibromide.

There are a few published data on reactions of tellurium tetrabromide with acetylenes [1, 2]. The addition of TeBr4 to phenylacetylene and hept-1-yne was reported to give bis(2-bromo-2-phenylvinyl)tellurium dibromide and bis(2-bromohept-1-en-1-yl)tellurium dibromide in 89 and 70% yield, respectively, as mixtures of Z and E isomers, the former prevailing [1]. We have developed an efficient procedure for the synthesis of E,E-bis(2-bromovinyl)tellurium dibromide in 96% yield by reaction of tellurium tetrabromide with acetylene [2]. The reaction was carried out in chlorooform under an acetylene pressure of 12–14 atm at 40–70°C. The addition of tellurium tetrachloride to acetylene, depending on the conditions, led to the formation of both bisand monoadducts, E,E-bis(2-chlorovinyl) tellurium dichloride and E-(2-chlorovinyl)tellurium trichloride [3]. Unlike vinyltellurium trichlorides, vinyltellurium tribromides have not been reported previously. Z isomers [1, 4, 5]. We detected no possible Z-configured product in the reaction of tellurium tetrabromide with acetylene. The process was stereoselective anti-addition. Presumably, the reaction involves formation of three-membered cyclic tellurirenium intermediate, as in electrophilic anti-addition of sulfenyl and selenenyl halides to triple C≡C bond through thiirenium and selenirenium cations [6]. It is known that compounds containing a 2-bromovinyltellanyl group are used in stereoselective syntheses of alkenes via consecutive replacement of bromine and tellurium atoms by organic groups in cross-coupling reactions [4]. To conclude, we have developed an efficient procedure for the stereoselective synthesis of (E)-2-bromovinyltellurium tribromide (I) which is promising as intermediate product and building block for organic synthesis and is the first representative of previously unknown vinyltellurium tribromides. (E)-2-Bromovinyltellurium tribromide (I). Light grey powder which darkens on heating to 60–64°C and begins to decompose. H NMR spectrum, δ, ppm: 7.56 d and 7.92 d (1H each, J = 13.5 Hz). C NMR spectrum, δC, ppm: 120.04 (CHBr), 137.72 (TeCH). Found, %: C 4.88; H 0.38; Br 68.02; Te 27.45. C2H2Br4Te. Calculated, %: C 5.08; H 0.43; Br 67.54; Te 26.96. The H and C NMR spectra were recorded on a Bruker DPX-400 spectrometer at 400.13 and 100.61 MHz, respectively, using DMSO-d6 as solvent and hexamethyldisiloxane as internal reference. This study was performed in the framework of the Basic Research Program of the Russian Academy of ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 9, pp. 1397–1398. © Pleiades Publishing, Ltd., 2013. Original Russian Text © M.V. Musalova, V.A. Potapov, M.V. Musalov, S.V. Amosova, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 9, pp. 1413–1414.

We presented the results on the preparation of high-purity monoisotopic varieties of silicon and germanium. The process involves the separation of isotopes in the form of SiF4 and GeH4 by centrifugation, ultrapurification of volatile compounds, and preparation of poly and single crystals. The attained degree of isotopic and chemical purities of single crystals obtained was shown. The content of the main isotope in the single crystals of 28Si is >99.99% and those in the single crystals of 29Si and 30Si are >99.9%. The specific resistivity of the 28Si single crystals is ∼1 kOhm cm and those of 29Si and 30Si are about 100–150 Ohm cm. The samples of the 76Ge single crystals have the main isotope content of >88 at.% and the difference concentration of electrochemically active impurities of 5·1010 cm−3. The main isotope content in the 74Ge polycrystal is 99.93 at.%. The optical and thermophysical properties of the isotope-enriched silicon and germanium single crystals were measured, which suggest a significant effect of the isopotic composition on thermal capacity, thermal conductivity, luminiscence, and light absorption.

The reaction of selenium dichloride, which can be prepared in situ from selenium and sulfuryl chloride, with acrylic acid (IIa), ethyl acrylate (IIb), or acrylonitrile at -20°C gives the corresponding selenides (II) in high yields.

In contrast to 2,6-dichloro-1,4-thiaselenane, the title dithiane is stable, even when refluxed in chloroform.

Thiaselenanes (II) are formed regioselectively as a result of anti-Markovnikov addition of selenium dihalide at the allyl group.

Also published in Chemistry of Heterocyclic Compounds , 2012, 48 (7), pp 1129-1131 http://link.springer.com/article/10.1007/s10593-012-1115-y

The reaction of diallyl selenide with selenium dichloride is chemo-, regio-, and stereoselective and affords the hitherto unknown diselenane (II) in good yield.

A highly chemo-, regio-, and stereoselective reaction of selenium dichloride with methacrylic acid leads to the unexpected formation of previously unknown diselenide (II).

The alkaline hydrolysis reaction of esters (I) and (III) proceeds with ANRORC rearrangement to give methyl ketones (II) and (IV), respectively.

We are performing systematic studies aimed at the ap plication of novel reagents, such as selenium dichloride and dibromide, in the chemistry of organoselenium com pounds.1—6 Although these reagents cannot be isolated in pure state and undergo disproportionation in solutions7, it has been shown1 that freshly prepared selenium dichloride and dibromide can be used as selective electrophilic re agents in the synthesis of organoselenium compounds. The reactions of selenium dichloride and dibromide with acet ylene,2 diphenylacetylene,3 divinyl sulfide,4 divinyl sul fone,5 divinyl selenide,6 propargyl alcohols,8 2,3 di methoxybuta 1,3 diene9 have been studied. In contrast to selenium tetrahalides, whose reactions with organic sub stances often afford mixtures of products10, the reactions of selenium dihalides proceed selectively to afford the tar get compounds in high yields.1—6,8,9 The use of selenium dihalides for annulation of phenyl ethers containing unsaturated groups by combination of the addition to the unsaturated bond and electrophilic sub stitution in the ortho position of the benzene ring is of the utmost interest. There are no data on annulation of phenyl propargyl ether with selenium halides. We studied the reaction of selenium dichloride with phenyl propargyl ether and found the conditions that al low selective preparation of previously unknown E 3 chloromethylidene 2,3 dihydro 1,4 benzoxaselenine (1). The highest yield of product 1 (80%) was obtained upon mixing reagents at low temperature (–60 °C) in chloro form followed by heating the reaction mixture to the boil ing temperature of the solvent. One can assume that the addition of selenium dichlo ride to the propargyl group occurs at low temperature and the second step, viz., electrophilic aromatic substitution, requires heating of the reaction mixture. The structure of product 1 was established by 1H, 13C (including JMOD), and 77Se NMR spectroscopy and con firmed by the data from mass spectrometry and elemental analysis. The value of spin spin coupling constant (100 Hz) between the selenium atom and the double bond carbon atom having no protons corresponds to the C—Se direct constant (JC—Se), which is evidence of the addition of the selenium atom to the central carbon atom of the propargyl group. The E configuration of product 1 was established using the NOESY spectra. The regio and stereospecificity of the process can be explained by the fact that the reaction proceeds via the intermediate selenirenium ion А, which is attacked by the chloride ion at the sterically unshielded terminal car bon atom. Thus, we showed for the first time the possibility of annulation of the selenium containing heterocycles to the benzene ring based on the reaction of selenium dichloride with unsaturated organyl phenyl ethers, where the addi tion of selenium halides to the unsaturated bond of orga nyl phenyl ethers and electrophilic aromatic substitution is combined.

Thiaselenole derivative (I) rearranges by nucleophilic substitution and subsequent ring expansion to furnish the hitherto unknown dihydrothiaselenine (III), obtained together with polymerization products.

The reaction of methyl anthranilate (I) with title compound (II) leads exclusively to quinazolinone (III) rather than its isomer (IV).

Depending on the conditions, reactions of phenylethers (I) and (III) with selenium dihalides can be directed selectively either to annulation or to formation of bis-adducts.

The regio- and stereoselective reaction of selenium dichloride with allyl phenyl ether (I) yields a new heterocyclic compound, dihydrobenzoxaselenine (II).

Addition of TeCl4 to acetylene affords hitherto unknown (E,E)-bis(chlorovinyl)tellurium dichloride (II), which represents a promising intermediate for the synthesis of organotellurium products.

Selenium dichloride and dibromide were not isolated as individual substances. It is known that selenium dichloride in solution exists in equilibrium with selenium tetrachloride and Se2Cl2, whereas the equilibrium of selenium dibromide in solution involves Se2Br2 and bromine [1, 2]. We were the first to reveal that freshly prepared selenium dichloride and selenium dibromide can be used in selective synthesis of organic selenides [3, 4]. Reactions of selenium dichloride and dibromide with divinyl chalcogenides and their derivatives opened a synthetic route to new heterocyclic compounds [5–10]. In continuation of our systematic studies on the chemical properties of selenium dihalides [3–10], we examined previously unknown addition of selenium dichloride to divinyl sulfone. It was found that the reaction occurs with high regioselectivity and leads to the formation of a new four-membered heterocyclic compound, 2,4-bis(chloromethyl)-1,3-thiaselenetane 1,1-dioxide (I). The yield of compound I was 85%, calculated on the reacted divinyl sulfone, the conversion of the latter being 58%. sional correlation techniques, as well as by mass spectrometry and elemental analysis. According to the NMR data, compound I was isolated as a mixture of two diastereoisomers at a ratio of 2.5 : 1. 2,4-Bis(chloromethyl)-1,3-thiaselenetane 1,1-dioxide (I). mp 76–77°C. Major diastereoisomer: H NMR spectrum, δ, ppm: 3.91 d.d (2H, CH2Cl, J = 11.8, J = 7.1 Hz), 4.27 d.d (2H, CH2Cl, J = 11.8, J = 7.1 Hz), 5.52 d.d (2H, CHSe, J = 7.1, 7.1 Hz). C NMR spectrum, δC, ppm: 41.39 (CH2Cl), 69.36 (CHSe). Se NMR spectrum: δSe 193 ppm. Minor diastereoisomer: H NMR spectrum, δ, ppm: 3.93 d.d (2H, CH2Cl, J = 11.9, J = 7.7 Hz), 4.31 d.d (2H, CH2Cl, J = 11.9, J = 7.9 Hz), 5.54 d.d (2H, CHSe, J = 7.7, 7.9 Hz). C NMR spectrum, δC, ppm: 41.63 (CH2Cl) , 70.03 (CHSe) . Se NMR spectrum: δSe 200 ppm. Mass spectrum, m/z (Irel, %): 268 (29) [M], 204 (12), 169 (100), 142 (56), 133 (34), 107 (82), 93 (24), 81 (13), 61 (19), 53 (21). Found, %: C 17.69; H 2.21; Cl 26.30. C4H6O2Cl2SSe. Calculated, %: C 17.93; H 2.26; Cl 26.46. The NMR spectra were recorded from solutions in CDCl3 on a Bruker DPX-400 instrument at 400.13 (H, HMDS), 100.61 (C, HMDS), and 76.30 MHz (Se, Me2Se). The mass spectrum (electron impact, 70 eV) was obtained on a Shimadzu GCMS-QP5050A instrument. This study was performed in the framework of the Basic Research Program of the Russian Academy of Sciences (project no. 5.1.8).

Products (IV) and (VII) are formed during purification by silica gel chromatography via dehalogenation of the primary products (III) and (VI).

An efficient method for the synthesis of oligodeoxyribonucleotides with alky1amino groups based on the H-phosphonate method and the Atherton- Todd reaction has been developed. During the synthesis internucleotide phosphorodiester groups did not react with the activated H-phosphonate.

(1991). SYNTHESIS OF DIALLYL SELENIDE. Organic Preparations and Procedures International: Vol. 23, No. 2, pp. 207-208.