Stability and microtox response of butenyltin compounds

Tributenyltin bromides containing double bonds at carbon atoms C-1, C-2 or C-3 were synthesized from symmetrical tetrabutenyltins. Although all three tetrabutenyltin compounds were stable, only the tributenyltin bromides with double bonds at C-1 and C-3 were sufficiently stable for further studies. In aqueous sodium bromide (NaBr) solution containing 1% acetone, tri-1-butenyltin bromide was more stable in sunlight than tri-3-butenyltin bromide, yet neither compound was as stable as tributyltin bromide. Stability in seawater, in the absence of ultraviolet (UV) light, was less for both tri-1-butenyltin bromide and tri-3-butenyltin bromide than for tributyltin bromide. The relative toxicities of the tributenyltin bromides were determined using a bioluminescent bacteria assay. The concentrations of tributenyltin bromides necessary to produce a toxic response were three to six times greater than for tributyltin bromide.     

Indium-mediated allylation/propargylation of α-diazoketones: a facile synthesis of 1-bromo-2-alkyl- or 2-arylpent-4-en-2-ols

α-Diazoketones undergo smooth allylation with successive bromide insertion with allylindium bromide generated in situ from allyl bromide and indium metal to produce 1-bromo-2-alkyl- or 2-arylpent-4-en-2-ols in high yields. Addition of propargylindium bromide produces 1-bromo-2-alkyl-or 2-arylpent-4-yn-2-ols under similar conditions.     

The constitution of the grignard reagent VII. The degree of association of ethylmagnesium compounds in diisopropyl ether

The degrees of association of ethylmagnesium bromide, diethylmagnesium and of a mixture of diethylmagnesium and magnesium bromide in the weakly basic solvent diisopropyl ether have been measured at concentrations up to 0.040 M at 27.7°. It is concluded that: (1), ethylmagnesium bromide is present as a dimer, (2), diethylmagnesium is present in a dimer-tetramer equilibrium with K₁ = 24.9 1/mol, and (3), when magnesium bromide is added to an excess of diethylmagnesium it reacts to form ethylmagnesium bromide. Diethylmagnesium and ethylmagnesium bromide are also in equilibrium with (EtMgBr·Et₂Mg), with K₃ approximately 2.5.     

Dosage polarographique du brome a l'echelle du nanogramme: Application à la determination du brome sanguin et urinairePolarographic determination of bromide at nanomolar levels. Application to the determination of bromide in blood and urine

Polarographic determination of bromide at nanomolar levels. Application to the determination of bromide in blood and urine.Colorimetric methods for bromide determination lack adequate sensitivity for normal levels in biological fluids. A sensitive amplification process is recommended: bromide is oxidized to bromate with hypochlorite; after reaction between bromate and excess of bromide, the bromine formed is extracted into chloroform and then reduced to bromide by ammonia; these different steps can be repeated. Alternating current polarography of bromate allows selective evaluation in biological fluids. The detection limit is 10^-6 M and can be reduced to 10^-9 M with further amplification steps. The effects of iodide and of instrumental parameters are discussed.     

The reaction OF N‐dichlorophosphoryl‐ P‐trichlorophosphazene with alkyl grignard reagents

The reactions of N‐dichlorophosphoryl‐P‐trichlorophosphazene Cl₃PN P(O)Cl₂ ( 1 ) with benzylmagnesium bromide, 2‐phenylethylmagnesium bromide, trimethylsilylmethylmagnesium chloride, n‐butylmagnesium bromide, cyclohexylmagnesium bromide, cyclopentylmagnesium bromide, tert‐butylmagnesium bromide, iso‐propylmagnesium bromide, and ethylmagnesium bromide were studied. Tri‐ and pentaalkyl phosphazenes were obtained in very poor yield from trimethylsilylmethylmagnesium chloride and cyclohexylmagnesium bromide, respectively. Trialkylphosphoryl compounds formed from benzyl‐, 2‐phenylethyl‐, and n‐butylmagnesium bromide. No phosphorus compound could be isolated from the reaction of 1 with t‐butyl‐, cyclopentyl‐, iso‐propyl‐, and ethylmagnesium bromide. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:413–416, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10153     

Reactions in microemulsion media. Nucleophilic displacement reaction of benzyl chloride with bromide ion

A kinetic and synthetic study of the reaction of benzyl chloride with bromide ion has been performed in microemulsions composed of cetyltrimethylammonium bromide, 1-butanol, water, potassium bromide, and hexane; rates and yields of benzyl bromide formation decreased with increasing hexane content.     

烯丙基溴化钐与羰基化合物反应合成高烯丙基醇

高烯丙基醇是有机合成中的一类非常重要的中间体,以烯丙基金属试剂与羰基化合物加成反应为其主要合成方法,常用的金属烯丙基化合物有烯丙基锂(镁、锌、硼、铟、硅、锡、钛)等.由于烯丙基的Grignard试剂制备过程中常伴随着大量的烯丙基偶联反应,所以用烯丙基的Grignard试剂来合.     

[Zn(NCS)4]2−-Selective electrodes based on higher quaternary ammonium salts (QAS)

We have studied analytical parameters of tetrarhodanozincate-selective film electrodes based on high-lipophilic quaternary ammonium salts: trinonyloctadecylammonium iodide, R-trioctadecylammonium bromide, R-trimethylammonium nitrate, R-tricetylammonium bromide, R-triethylammonium bromide, R-tributylammonium bromide, R-trilaurylammonium bromide, where R is 3,4,5-tris(dodecyloxy)benzyl. A procedure has been developed for the study of the molecular extraction of zinc rhodanide with membrane plasticizers. The applicability of these electrode to zinc determination in solid wastes has been demonstrated.     

The reactions of perfluoroalkanesulfonyl bromide with hetero-atom substituted olefinic bonds

Perfluoroalkanesulfonyl bromides reacted with vinyl bromide, vinyl acetate and trimethyl vinyl silane to give the corresponding adducts with the evolution of SO₂. Perfluoroalkanesulfonyl bromide reacted with trimethyl silyl enol ether followed by hydrolysis to give the corresponding α-bromoketones and perfluoroalkanesulfinic acid. However, perfluoroalkanesulfonyl chlorides reacted with trimethyl silyl enol ether of pinacolone on UV irradiation to give the corresponding α-perfluoroalkyl derivatives of pinacolone. Under mild condition, perfluoroalkanesulfonyl bromide also brominated phenol and anisole to give the corresponding p-bromo derivatives. Sodium α, α-dichlorotrifluoroethanesulfinate reacted with bromine in water at 25°C to form α, α-dichlorotrifluoroethanesulfonyl bromide which was thermally less stable than but similar in reactivity to perfluoroalkanesulfonyl bromide.     

Determination of iodide and bromide by ion chromatography with post-column reaction detection

During an investigation into the mechanism of the biosynthesis of thyroid hormones, it became necessary to determine traces of iodide and bromide in biological matrices as well as in food. A vydac 302-IC anion-exchange column with methanesulphonic acid as the mobile phase was used for the ion chromatographic separation of iodide and bromide. A post-column reaction detector was developed based on the reaction between iodide or bromide, chloramine-T and 4,4'-bis(dimethylamino)diphenylmethane. Methods with minimal sample preparation are described for determination of iodide or bromide in serum, milk, salt and water. The detection limit is ca. 20 pg iodide and 15 ng bromide injected.     

The Reaction of Ethyl Bromoacetate with Dimethyl Sulfoxide

The reaction of excess dimethyl sulfoxide with ethyl bromoacetate has been shown to produce ethyl glyoxylate, hydrogen bromide, and dimethyl sulfide. The yield of glyoxylate at first was reduced because the dimethyl sulfide reacted with bromoacetate to form trimethylsulfonium bromide and ethyl (methylmercapto) acetate, presumably via carbethoxymethyldimethylsulfonium bromide. These side reactions were diminished in a thin-film reactor, but the result was not satisfiable, the yield was 51%, and the side reactions were prevented by addition of methyl bromide, which rapidly consumed the dimethyl sulfide with formation of trimethylsulfonium bromide. Addition of 1, 2-epoxy-3-phenoxypropane removed the hydrogen bromide, thereby preventing the deleterious effects casued by its reduction of dimethyl sulfoxide to dimethyl sulfide. In this way has been developed a convenient preparation of ethyl glyoxylate in yields averaging about 70%. Identification and stoichiometry of the reaction products are presented.     

Use of <Superscript>82</Superscript>Br and <Superscript>131</Superscript>I radionuclides in studies of goitrogenic effects of exogenous bromide

The interference of excessive bromide intake with iodine metabolism in the rat was studied using ⁸²Br and ¹³¹I radionuclides. Mainly lactating rat dams and their pups were used, in addition to adult male rats, in the present studies. Particularly, the influence of high bromide intake in lactating rat dams on the transfer of iodine and bromide to suckling young through breast milk was evaluated. The induction of hypothyroid status in the pups by high bromide intake in the mothers was proved unambiguously. Excessive bromide in lactating rat dams caused a marked decrease in plasma levels of thyroid hormones both, in the mothers and in their sucklings. The effects of an enhanced bromide intake on the thyroid function in relation to iodine status in the animals were also followed. Marked goitrogenic and thyrotoxic effects of excessive bromide in adult rats were significantly enhanced under the conditions of simultaneous iodine deficiency in the experimental animals.     

An inexpensive modification of the Simmons-Smith reaction: The formation of bromomethylzinc bromide as studied by NMR spectroscopy

Bromomethylzinc bromide, prepared from zinc metal and methylene bromide in tetrahydrofuran, gives moderate to good yields of cyclopropanation product when treated with olefins, thus providing an inexpensive alternative to the Simmons-Smith procedure. An NMR study of the reaction between metallic zinc and methylene bromide has been carried out: in addition to bromomethylzinc bromide and dimethylzinc, two further species were observed and tentatively identified as bis(bromomethyl)zinc and a di- or tri-zinc compound.     

全氟烷基磺酰溴与杂原子取代烯键的反应

全氟烷基磺酰溴与杂原子取代烯烃, 如溴乙烯, 乙酸乙烯酯, 三甲基硅乙烯加成, 得相应的加成物, 与烯醇硅醚反应, 水解后得到α位溴代酮和全氟烷基亚磺酸. 全氟磺酰氯与1-三甲基硅氧基-1-叔丁基乙烯在紫外光照下反应, 生成α位全氟烷基化的酮. 全氟烷基磺酰溴溴化苯酚和甲氧基苯, 得到对位溴化产物. α,α-二氯三氟乙基亚磺酸钠与溴水在20-25℃反应, 得α,α-二氯三氟乙基磺酰溴, 其化学反应性与全氟烷基磺酰溴类似, 但稳定性较差.     

Molecular absorption spectrometry (MAS) by electrothermal evaporation in a graphite furnace-IX Determination of traces of bromide by mas of AlBr after liquid-liquid extraction of bromide with triphenyltin hydroxide

The determination of traces of bromide by molecular absorption spectrometry (MAS) of AlBr (with electrothermal volatilization) is described. It is possible to determine 25 ng of bromide. Many problems are caused by various matrices, so an extraction method for separation (and also preconcentration) was developed. The combination of bromide extraction with triphenyltin hydroxide, stripping with 0.025M barium hydroxide and determination of the extracted bromide by MAS of AlBr (after addition of aluminium ions) gives a very sensitive and selective method for determination of traces of bromide in micro or macro samples, in the presence of large amounts of other species, including chloride and iodide.     

气相色谱-串联质谱法测定2-氰基溴苄中3-氰基溴苄和4-氰基溴苄的含量

建立了气相色谱-串联质谱法测定苯甲酸阿格列汀关键起始物料2-氰基溴苄中基因毒性杂质3-氰基溴苄和4-氰基溴苄含量的分析方法。采用50%苯基-50%二甲基聚硅氧烷为固定液的VF-17MS毛细管柱(30m×0.25mm,0.25μm)进行程序升温;进样口温度260℃;以多反应监测(MRM)模式检测。2种待测物均具有较好的线性关系,相关系数均大于0.998 0;检出限(3S/N)均为2.0μg·L^-1;3-氰基溴苄的回收率为92.1%~97.0%;4-氰基溴苄的回收率为102%~109%;供试品溶液、杂质对照品溶液和系统适用性溶液在室温(25℃)下放置18h内稳定。三批生产规模样品中均未检出3-氰基溴苄和4-氰基溴苄。建立的分析方法灵敏度高、分离度好、结果准确,可有效分离并测定2-氰基溴苄中的3-氰基溴苄和4-氰基溴苄含量,为苯甲酸阿格列汀的安全性提供了保障。     

4－N－茄呢基氨基苯甲酸糖酯的合成

在氢氧化钠和四丁基溴化铵存在下，将化合物4－N－茄呢基氨基苯甲酸（3） 分别与O－乙酰基溴代葡萄糖、O－乙酰基溴代半乳糖、O－乙酰基溴代乳糖和O－乙 酰基溴代麦牙糖反应制得对应的糖酯4a-4d，由元素分析，IR，~1H NMR，~(13)C NMR和MS确证了四个新化合物的结构，并做了几种抗癌生理活性测试。     

Influence of additives on the clouding behavior of amphiphilic drug solutions

The present work focuses on the clouding phenomenon in an amphiphilic drug [amitriptyline (AMT), which is a tricyclic antidepressant] solution. A 50-mM AMT solution prepared in 10 mM of sodium phosphate (SP) buffer was taken where the cloud point (CP) was found to decrease with increasing pH. The same CP decreasing trend (with pH increase) followed in the presence of a fixed concentration (50 mM) of added salts [NaBr, and tetra-n-butylammonium bromide (TBuAB)]. The addition of increasing amounts of quaternary bromides (tetramethylammonium bromide, tetraethylammonium bromide, tetra-n-propylammonium bromide, TBuAB, and tetra-n-pentylammonium bromide) to 50 mM of AMT solution (prepared in 10 mM of SP buffer) caused continuous increase in CP, which was found to be dependent upon the alkyl chain length of that particular salt. The similar type of CP increase was also observed in the presence of conventional (cetyltrimethylammonium bromide and tetradecyltrimethylammonium bromide) and gemini surfactants [bis(hexadecyldimethylammonium)hexane, bis(hexadecyldimethylammonium)pentane, and bis(hexadecyldimethylammonium)butane]. The overall behavior was discussed in terms of electrostatic interactions, micellar growth, and mixed micelle formation.     

Synthesis of 2,3-Dihydro-1H-imidazo[1,2-a]pyridinium Systems by Halocyclization of 1-Alkenyl(propargyl)-2-aminopyridinium Halides

Russian Journal of General Chemistry - Reaction of 2-aminopyridine with allyl bromide, methallyl chloride, 2-bromoallyl bromide, and propargyl bromide in acetone furnished 2-amino-1-allyl-,...     

Polymerization of aromatic nuclei. XXVI. Poly(p-phenylene): Friedel–crafts alkylation,molecular weight,and propagation mechanism

Poly(p-phenylene) was alkylated with n-propyl bromide, n-propyl chloride, and isopropyl bromide in the presence of aluminum chloride. Apparently, the reactions involve dialkylation with n-propyl halides and alternating mono- and dialkylation with isopropyl bromide. Alkylation with ethyl or n-butyl bromide was unsuccessful. The dialkylated polymer was sufficiently soluble to allow molecular weight determination. Mechanistic aspects of alkylation and propagation are treated.