Synthesis of 2-thiobenzimidazole derivatives as potential antifilarial agents

Several 5-benzoyl-2-thiobenzimidazole and 2-thiobenzimidazole aliphatic acids, esters, and N,N-dialkyl-carboxamides and thiocarboxamides were prepared by reacting bromo aliphatic acids, bromo aliphatic esters, and N,N-dialkylcarbamoyl or thiocarbamoyl chlorides with 5-benzoyl-2-thiobenzimidazole or 2-thiobenzimidazole in the presence of base. 2-Thiocarbomethoxy- and 2-thiocarboethoxybenzimidazole were prepared by the reaction of 2-thiobenzimidazole with methyl or ethyl chloroformate in the presence of base. However, the reaction of 5-benzoyl-2-thiobenzimidazole with ethyl chloroformate, afforded 5-benzoyl-2-ethylthiobenz-imidazole.     

The phase behavior of tetramethyl bisphenol-A polyarylate/aliphatic polyester blends

The phase behavior of blends of tetramethyl bisphenol-A polyarylate (TMPAr) with various linear aliphatic polyesters characterized by the ratio of aliphatic carbons to ester groups in the repeating unit, CH₂/COO = 3 ∼ 9, was examined by differential scanning calorimetry and dynamic mechanical analysis. TMPAr/aliphatic polyester blends prepared by solvent casting were found to be miscible when the CH₂/COO ratio of aliphatic polyesters was larger than 4 and up to 9. The thermodynamic interaction parameter, B for the miscible blends was determined by the analysis of the depression of the melting point of polyester using the Hoffman-Weeks method. From the analysis of the heat of mixing data using a binary interaction model, it was concluded that strong unfavorable intramolecular interaction exists between the  CH₂ and  COO units in aliphatic polyesters and that four substituted methyl groups produces more favorable effects on the miscibility TMPAr with aliphatic polyesters. © 1998 John Wiley & Sons, Inc. J Polym Sci 36 : 201–212, 1998     

脂肪族聚酰胺热膨胀行为的研究

通过热膨胀测试,示差扫描量热分析(DSC)、广角X射线衍射(WAXD)与傅里叶变换红外光谱(FTIR)等方法研究了4种脂肪族聚酰胺玻璃化转变温度(Tg)、结晶行为以及氢键强度对热膨胀行为的影响,探索了影响脂肪族聚酰胺热膨胀的本质.DSC和X射线衍射结果表明,聚酰胺中结晶部分的热膨胀系数要低于无定形部分,但聚酰胺的熔融温度和结晶度对热膨胀的影响不够明确.相比较其它脂肪族聚酰胺,聚酰胺56(PA56)具有较高的玻璃化转变温度和较低的亚甲基/酰胺基(CH2/CONH)比例,表现出较低的热膨胀系数.研究发现,在相同条件下制备的脂肪族聚酰胺体系中,CH2/CONH比例或Tg与热膨胀系数具有明显的线性关系,随着CH2/CONH比例的降低或Tg的升高,热膨胀系数显著减小.FTIR的结果表明,聚酰胺分子链间的氢键密度和氢键强度随温度升高衰减的程度是影响其热膨胀行为的关键因素.     

FTIR study of E7 liquid crystal orientations confined to cylindrical cavities of Anodisc membranes

The orientation of E7 liquid crystal (LC) confined within 200 nm diameter cylindrical cavities of Anodisc membranes was investigated by FTIR dichroism techniques. The cavity walls of the confining pores were chemically modified with different length aliphatic acids (C_nH_2n+1COOH, n=5, 6, 7, 9) at 2 and 4% concentrations. From the FTIR spectra of the aliphatic acid-treated alumina Anodsic membranes, we found salt formation between the -COOH group of the aliphatic acids and the Anodisc membranes. From the FTIR spectra of LC-filled Anodisc membranes, we found an abrupt alignment direction change, from parallel to perpendicular, of the LC molecules along the long axis of the cavities between n=6 and n=7 for the 2% concentration of aliphatic acid. However for the 4% concentration of aliphatic acid the parallel to perpendicular alignment direction of LC molecules changed between n=5 and n=6. The same trend was previously observed for ²H NMR measurements by other researchers.     

芳香-脂肪族共聚酰胺溶致液晶行为的研究

本文对脂肪族二元胺(ADA、NH_2(CH_2)_nNH_2、n=2、6、8、10、12),对苯二胺(PPD)和对苯二甲酰氯(TPC)三元芳香-脂肪族共聚酰胺硫酸溶液的溶致液晶性能进行了研究.利用偏光显微镜、小角和宽角X-光衍射确定了该类共聚酰胺溶致液晶中介相的类型随共聚物中脂肪族二胺链单元含量的变化规律.     

Hydrogen Bonded Semi-Rigidified Bispyridyl-Incorporating Aryl Amide Oligomers： Efficient ＂C＂-Styled Receptors for Aliphatic Ammoniums,a Remarkable Protonation Effect and Chiral Induction

The complexing behaviour of two linear compounds 1 and 2 toward the trifluoroacetic acid （TFA） salts of n-dodecylamine, di-n-octylamine, n-dodecyl D- and L-phenylalaninates （3, 4, and D- and L-5） in chloroform has been described. Compounds 1 and 2 consist of two folded amide moieties with two pyridyls at the terminals which are connected directly or with an acetylene linker. The rigidified folded moieties are stabilized by intramolecular hydrogen bonding, while the whole molecules can adopt an ＂S＂- or a ＂C＂-styled conformation depending on the relative orientation of the two rigidified moieties. ^1H NMR, UV-Vis, fluorescent and circular dichroism investigations revealed that 1 and 2 could bind primary and secondary ammonium cations with their ＂C＂-styled conformation. In the presence of 1 equiv, of TFA, the binding stability was increased significantly as a result of promoted formation of the ＂C＂-styled conformation due to the monoprotonation of the peripheral pyridyl units in 1 and 2. In contrast, the addition of 2 equiv, of TFA substantially weakened the binding stability because the ＂S＂-styled conformation was favored as a result of protonation of both of their pyridyl units. Moreover, remarkable induced circular dichroisms were also displayed for the complexes of 1 and 2 with chiral D- and L-5.     

CpTiCl3-LiAIH4体系的研究——环状缩醛和缩酮的还原

去来川等人曾对Cp₂TiCl₂和LiAlH₄反应生成的钛-铝络合物的结构、组成及其催化作用进行了详细研究,佐滕等人曾以Cp₂TiCl₂作催化剂,用LiAIH₄还原丙烯醇和苄醇等化合物,结果羟基被还原,我们曾用Cp₂TiCl₂-LiAlH₄体系对芳香族的二元醇、二元酮及其它有机官能团的还原进行了研究。     

New method for preparing saturated and unsaturated aliphatic polyurethanes

Saturated and unsaturated aliphatic polyurethane were obtained from three different routes. In route 1, 1,4-dichloro-2-butene, sodium cyanate, and methanol were reacted to give dimethyl 2-butene-1,4-dicarbamate. This is hydrogenated easily to give dimethyl butane-1,4-dicarbamate. Ester exchange reaction of this compound with glycol gave saturated aliphatic polyurethane. In another procedure, route 2, 1,4-dichloro-2-butene, sodium cyanate and excess glycol were reacted to give bis(ω-hydroxyalkyl)-2-butene-1,4-dicarbamate. This was hydrogenated to give bis(ω-hydroxyalkyl)-butane-1,4-dicarbamate. A glycol elimination reaction gave poly(polymethylene tetramethyl-enedicarbamate). By route 3, 1,4-dichloro-2-butene, sodium cyanate, and glycol were reacted to give poly(polymethylene 2-butene-1,4-dicarbamate), a new unsaturated aliphatic polyurethane.     

M_2S_3-SO_4~(2-)型催化剂合成高级脂肪酸酯

１引言脂和国民经济关系密切,既是人类食物的重要组成部份和重要的营养物质,又是工业用途广泛的原料。工业上由乙醇与脂肪酸经硫酸液相催化合成酯［‘”’］,但此法副反应多,设备腐蚀严重,后处理工序繁琐,三废处理困难。采用超强酸催化高级脂肪酸酯的合成,可以避免上述缺点。而且这类催化剂可在高温下使用,相对于液体强酸型催化剂ｌ‘１,它们以其不同寻常的酸强度使许多难以进行的反应在很温和的条件下进行,并且具有能耗低、无腐蚀、无污染、工艺简便、用量少、易再生等,因而得到越来越广泛的应用。２实验部分２．１试剂及纯废月…     

Syntheses of Substituted 2-Phenyl α β-Unsaturated Aliphatic Acids

Additions of long chain aliphatic aldehydes in controlled basic media on 5-hydroxy 2-coumaranone or on 3-isochromanone give the corresponding ene-lactones (46–55%). Hydrolysis of the lactone ring leads to substituted 2-phenyl α β -unsaturated aliphatic acids from which stable K-salts or methyl esters were obtained.     

A simple radical addition-elimination route to geometrically pure (E)-alkene and chromanone derivatives via beta-nitrostyrene

Various geometrically pure (E)-beta-alkyl-styrenes have been synthesized by the radical NO(2) substitution of alkyl moieties generated via hydrogen abstraction followed by decarbonylation from aliphatic aldehydes. These reactions, which involve a high chemical selectivity and regioselectivity constitute a new route to (E)-beta-alkylstyrenes. Both aliphatic and aromatic aldehydes can be used in this novel reaction. When 2-allyloxybenzaldehyde was used, the benzoyl radical added directly to the double bond without decarbonylation to give the 3-cinnamylchroman-4-one. This unique difference between aliphatic and aromatic aldehydes represents a simple route for the synthesis of biologically important chromanones.     

分子诱导效应指数与脂肪族醛酮的沸点

利用分子诱导效应指数，建立了三参数方法计算脂肪族醛酮沸点的关系式： ln(820．5—Tb)＝6．38327—1．23961×10^-1Nc+1．95353△I+6．68434×10^- 2N，式中Nc为脂肪族醛酮中烷基部分的有效碳链长度；△I为具有相同碳原子数目 的支链烷基与直链烷基的诱导效应指数的差值，它表示羟基对醛酮沸点的影响；N 为碳原子数．     

A comparative molecular similarity index analysis (CoMSIA) study identifies an HLA-A2 binding supermotif

The 3D-QSAR CoMSIA technique was applied to a set of 458 peptides binding to the five most widespread HLA-A2-like alleles: A^*0201, A^*0202, A^*0203, A^*0206 and A^*6802. Models comprising the main physicochemical properties (steric bulk, electron density, hydrophobicity and hydrogen-bond formation abilities) were obtained with acceptable predictivity (q ² ranged from 0.385 to 0.683). The use of coefficient contour maps allowed an A2-supermotif to be identified based on common favoured and disfavoured areas. The CoMSIA definition for the best HLA-A2 binder is as follows: hydrophobic aromatic amino acid at position 1; hydrophobic bulky side chains at positions 2, 6 and 9; non-hydrogen-bond-forming amino acids at position 3; small aliphatic hydrogen-bond donors at position 4; aliphatic amino acids at position 5; small aliphatic side chains at position 7; and small aliphatic hydrophilic and hydrogen-bond forming amino acids at position 8.     

Ion-chromatographic selectivity of polyelectrolyte sorbents based on some aliphatic and aromatic ionenes

An aliphatic ionene with hydroxyl group (2HP-8 ionene), mixed aliphatic-aromatic ionenes (3-X and 6-X ionenes), aromatic ionene (Ph-X ionene), and viologen (Dp-X ionene) - polymers with quaternary nitrogen atoms in the main chain served as modifiers in synthesising polyelectrolyte sorbents for ion chromatography. The selectivity of produced and several previously prepared anion exchangers was compared with those of aliphatic ionenes. It was found that aromatic ionenes having a rigid structure of polymer chains are similar to their aliphatic analogues with shorter chains with a high charge density. Polyelectrolyte sorbents based on aromatic ionenes show higher selectivity to aromatic acids (e.g., 1-naphthalenesulfonic acid) as compared with aliphatic ionenes due to specific pi-pi interactions.     

Synthesis of aliphatic ketones from allylic alcohols through consecutive isomerization and chelation-assisted hydroacylation by a rhodium catalyst

An allylic alcohol, utilized as a precursor for an aliphatic aldehyde, reacted with olefins to afford aliphatic ketones in the presence of RhCl(PPh(3))(3), 2-amino-4-picoline, aniline, and benzoic acid through a tandem reaction of an isomerization and a chelation-assisted hydroacylation.     

Highly selective room-temperature copper-catalyzed C-N coupling reactions

Through the use of cyclic beta-diketones as supporting ligands, the copper-catalyzed coupling of aryl iodides with aliphatic amines occurs at room temperature in as little as 1 h. These high reaction rates allow for the coupling of a wide range of aryl and heteroaryl iodides at room temperature. This method is highly tolerant of a number of reactive functional groups, including -Br and aromatic -NH2 as well as phenolic and aliphatic -OH. The high selectivity of the CuI-beta-diketone catalyst for aliphatic amines represents a useful complement to the palladium-based methods.     

Cyano-containing ionic liquids for the extraction of aromatic hydrocarbons from an aromatic/aliphatic mixture

Ionic liquids can replace conventional solvents in aromatic/aliphatic extractions, if they have higher aromatic distribution coef- ficients and higher or similar aromatic/aliphatic selectivities. Also physical properties, such as density and viscosity, must be taken into account if a solvent is applied in an industrial extraction process. Cyano-containing ionic liquids have a lower den- sity than the benchmark solvent sulfolane and a higher viscosity. Sulfolane is from a hydrodynamic point of view a better sol- vent than ionic liquids for the aromatic/aliphatic extraction. The most suitable ionic liquids for the extraction of aromatic hy- drocarbons from a mixture of aromatic and aliphatic hydrocarbons are [bmim]C(CN)3, [3-mebupy]N(CN)2, [3-mebupy]C(CN)3, [3-mebupy]B(CN)4 and [mebupyrr]B(CN)4. They have factors of 1.2-2.3 higher mass-based distribution coefficients than sul- folane and a similar or higher, up to a factor of 1.9 higher, aromatic/aliphatic selectivity than sulfolane. The IL [3-mebupy]N(CN)2 is a better extractant for the separation of toluene from a mixture of toluene/n-heptane in a pilot plant Ro- tating Disc Contactor (RDC) than sulfolane.     

Copper-catalyzed enantioselective conjugate addition of grignard reagents to acyclic enones

A highly enantioselective Cu-catalyzed addition of Grignard reagents to acyclic aliphatic enones is described. In the presence of 5 mol % of CuBr.SMe2 and 6 mol % of JosiPhos diphosphine aliphatic enones react with Grignard reagents to provide beta-substituted linear ketones with high yields, regio-, and enantioselectivities.     

Ion mobility spectra of cyclic and aliphatic hydrocarbons with different substituents

We investigated the influence of structural differences on the ionization pathways and drift behavior in ion mobility spectrometry for cyclic and aliphatic hydrocarbons with different functional groups. The sets of cyclic and aliphatic compounds had an identical mass or a mass difference of 2 Da. Therefore, mass effects can be neglected during the investigation of these compounds. Depending on the functional group, considerable differences were found in the detectable concentration ranges and in the number and position of product ion peaks in ion mobility spectra. The spectra of chlorinated compounds and hydrocarbons show no correlation to their calculated collisional cross sections. Differences in collisional cross section between cyclic and aliphatic substances investigated were only found to influence the drift times detected for amines and aliphatic aldehydes while complex ion chemistry was observed for the other substances.     

Promotion effect of nickel for Cu–Ni/γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts in the transfer dehydrogenation of primary aliphatic alcohols

Cu–Ni/γ-Al₂O₃ bimetallic catalysts were developed for anaerobic dehydrogenation of non-activated primary aliphatic alcohols to aldehydes. Systematic investigation about the promotion effect of nickel on the catalytic performance was carried out. Hydrogenation of C=C bond rather than C=O bond, was significantly improved over Cu–Ni/γ-Al₂O₃ catalyst by introducing nickel, which interprets the good conversion of primary aliphatic alcohols. This work would contribute to design new catalysts for dehydrogenation of primary aliphatic alcohols.