Toward a toolbox of functional block copolymers via free-radical addition of mercaptans

This work demonstrates the applicability of the free-radical addition of ω-functional mercaptans onto 1,2-polybutadienes as a modular synthetic pathway toward a toolbox of diverse functional block copolymers. Functional groups included, for instance electrolytes (carboxylic acid and amine), l-amino acid, and fluorocarbon. The number of functional groups attached to the polymer was lower than that of double bonds reacted (degree of functionalization=50–85%, typically 70–80%) due to cyclization of two neighboring units, but the narrow molecular-weight distribution of the parent (co)polymer was always maintained.     

Partialsynthesen von Cardenoliden und Cardenolid-Analogen. VII. Synthese A/B-cis- und C/D-cis-verknüpfter Steroidmono- und -bis(α-methylen-γ-butyrolactone)

Partial Syntheses of Cardenolides and Cardenolide Analogues. VII. Synthesis of A/B-cis- and C/D-cis-linked Steroidal Mono- and Bis (α-methylene-γ-butyrolactones) The synthesis of A/B-cis- and C/D-cis-linked steroidal mono- and bis(α-methylene-γ-butyrolactones) 10–13 , 18 and 24 by Reformatsky-type reaction of 3β-acetoxy-14-hydroxy-5β, 14β-androstan-17-one( 6 ), 14-hydroxy-5β, 14β-androstane-3,17-dione ( 8 ), 3β-acetoxy-14-hydroxy-5β,14β-pregnan-20-one ( 17 ) and 14-hydroxy-5β,14β-pregnane-3,20-dione ( 23 ), respectively, with ethyl α-(bromomethyl)acrylate is described. All steroidal lactones exhibit strong inhibitory activity on the proliferation of Ehrlich ascites carcinoma cells in suspension culture. For inhibitory activity the lactone moiety at C-17 of the steroid molecule is more important than the lactone moiety at C–3 and C–20, respectively.     

Transition metal catalysis in fluorous media: application of a new immobilization principle to rhodium-catalyzed hydrogenation of alkenes

Biphase systems were generated by combining toluene solutions of alkenes (2-cyclohexen-1-one, 1-dodecene, cyclododecene, 4-bromostyrene) and CF₃C₆F₁₁ solutions of the pre-catalyst ClRh[P(CH₂CH₂(CF₂)₅CF₃)₃]₃ ((1); 1.1–0.8 mol%) and placed under 1 atm of H₂. The perfluoroalkyl segments in (1) confer high affinities for fluorocarbons. After 8–26 h at 45°C, the CF₃C₆F₁₁ phases were separated, and extracted with an equal volume of toluene. GLC analyses of the toluene solutions showed 98–87% yields of the hydrogenation products cyclohexanone, dodecane, cyclododecane, and 4-bromoethylbenzene (turnover numbers 120–87). The CF₃C₆F₁₁ phases were charged with new toluene solutions of 2-cyclohexen-1-one or 1-dodecene, and similarly treated with H₂. There was no significant loss of catalyst activity over three cycles. A preparative reaction gave cyclohexanone in 89% yield. Some C=C isomerization could be detected during the course of 1-dodecene hydrogenation, and (1) gave a dihydride complex in the absence of alkene.     

屈螺酮关键中间体的合成研究

以NBS为溴源,3-特戊酰氧基-5β,6β-环氧-7β-羟基-15β,16β-二亚甲基-孕甾-17-酮为原料,在三苯基膦催化剂的作用下合成了屈螺酮的关键中间体3-特戊酰氧基-5β,6β-环氧-7α-溴-15β,16β-二亚甲基-孕甾-17-酮,考察了NBS的用量、催化剂的用量、反应温度、反应时间对3-特戊酰氧基-5β,6β-环氧-7α-溴-15β,16β-二亚甲基-孕甾-17-酮收率的影响。实验结果表明,最佳投料条件下目标物的质量收率为89.5%。该方法条件温和,操作简单,易于实现工业化生产。     

Hydrophilic surface formation on polymers by ion-assisted reaction

The wettability and adhesion of various polymers were improved using ion-assisted reaction (IAR) method, in which the polymer surfaces were irradiated by energetic ions in a reactive gas environment. The addition of new polar groups on polymer surfaces and permanent wettable polymer surfaces (water contact angle below 30° and surface free energy 60–70 mJ/m²) have been accomplished by IAR treatment. The changes in wettability and surface free energy were critically dependent on the ion dose, the ion beam energy and the flow rate of the reactive gas. Improvements in wettability and surface free energy are primarily attributed to the increase of polar components due to the formation of polar groups such as –(C=O)–, –(C=O)–O–, –(C–O)–, etc. The characteristics of the IAR treatment have been reviewed, with outstanding results regarding the wettability and adhesion of various polymers from polyolefin to fluoropolymers.     

Elucidation of cyclic fatty acid monomer structures. Cyclic and bicyclic ring sizes and double bond position and configuration

Gas chromatography (GC)-electron ionization mass spectrometry of 2-alkenyl-4,4-dimethyl-oxazoline derivatives was used to confirm the identities of a complex mixture of C₁₈ diunsaturated cyclic fatty acid monomers (CFAMs) that were isolated from heated flaxseed (linseed) oil. The positions of double bonds and 1,2-disubstituted unsaturated 5- and 6-membered rings along the fatty acid hydrocarbon chains were established by this method. The oxazoline spectra exhibited a homologous ion series with a pattern of peaks that were 14 u (u=atomic mass unit) apart but interrupted when a double bond (12-u mass interval) or a ring was present along the fatty acid chain. The identity and location of a ring were indicated by a large interval of 68, 82, 66, 80, 78, or 120 u for a saturated 5- or 6-membered ring, monounsaturated 5- or 6-membered ring, diunsaturated 6-membered ring, or monounsaturated bicyclic ring system (fused 5- and 6-membered rings), respectively. The double bond configuration for the methyl ester derivatives of these CFAMs was established by GC-matrix isolation-Fourier transform infrared spectroscopy. The elucidated alkenyl structures at C₂ in diunsaturated 2-[alkenyl]-4,4-dimethyloxazolines were 8-(2-but-trans-1-enyl-cyclopentenyl)octyl, 9-(2-propyl-cyclopentenyl)non-rans-8-enyl, 9-(2-propyl-cyclopentenyl)non-cis-7-enyl, 8-(2-but-cis-1-enyl-cyclopentenyl)ocytl, 9-(2-propylcyclopentenyl)non-cis-8-enyl, 8-(2-propyl-cyclohex-cis-4-enyl)oct-trans-7-enyl, 8-(prop-trans-1-enyl-cyclohex-cis-4-enyl)ocytl, and 8-(2-propylcyclohexa-cis,cis-3,5-dienyl)octyl. Physical science aide, 1991–1992; currently a medical student at the University of Maryland, Baltimore, MD.     

Six- and seven-membered 1-oxa-4-aza-2-silacyclanes as possible correctors of adaptational mechanisms

The biological activity of eight 1-oxa-4-aza-2-silacyclanes with the OSiCH(2)N fragment including 6-membered 2-sila-5-morpholinones (1-3) and 4-acyl-2-silamorpholines (4-6)and previously unknown 7-membered derivatives of salicylic acid (7, 8) was studied. Compounds 1 and 3-6 show the certain antihypoxic action. Compounds 2 (40 mg/kg), 4 (20 mg/kg), 6 (40 mg/kg), 7 (20 mg/kg) and 8 (40 mg/kg) reduce the physical serviceability of intact animals. Compound 1 (20 mg/kg) influences the physical serviceability in a moderate-positive way on the background of chlorophos-poisoning. Compounds 5-8 displayed protective properties against chlorophos-poisoning at the LD(50) dose and compounds 2, 4, 5, 7 at the LD(100) dose. Influence of compounds 1 and 2 on the emotional-research behavior of mice was studied.     

Catalytic oxidation of phenol in aqueous solutions

The objective of this work is to investigate catalyst systems for the oxidation of phenol in water in a batch autoclave. The main experimental variables are the type and the composition of the catalyst, the catalyst loading, temperature, oxygen partial pressure, initial phenol concentration and the stirrer speed. Commercial catalysts were used. Experimental work was conducted in two different laboratories. In one laboratory, the catalysts tested were 35% CuO+65% ZnO; 5–15% CuO+85–95% Al₂O₃; 26% CuO+74% Cu Chromite. In the other laboratory, the catalysts tested included 35% CuO+65% ZnO; 5–10% Ba₂CO₃+<5% C+30–40% CuO+60–70% ZnO; and 8–15% Al₂O₃+1–5% C+35–45% CuO+40–50% ZnO. With some of these catalysts depending on the operating conditions, complete phenol conversion could be obtained within 90 min. Under certain experimental conditions, the reaction underwent an induction period after which there was a transition to a much higher activity regime. The induction period may be due to an autocatalytic reaction system or to a very slow rate of formation of hydroquinone and catechol which then readily oxidize to o- and p-benzoquinone. An increase in the temperature and the oxygen partial pressure decreased the induction period, which increased as the catalyst to phenol ratio increased. 26% CuO+74% Cu Chromite and 8–15% Al₂O₃+1–5% C+35–45% CuO+40–50% ZnO were found to be the most active catalysts.     

Living cationic polymerization of vinyl ethers with a functional group

Summary Living polymerizations of 2-vinyloxyethyl methacrylate and 2-vinyloxyethyl cinnamate were successfully performed with a mixture of hydrogen iodide and iodine (HI/I₂) as an initiating system in toluene at –15 to –40 °C, Although the two monomers have an unsaturated ester pendant group, their living polymerizations proceeded exclusively via the vinyloxyl group without undesirable side reactions of the pendant group. The product polymers had a very narrow molecular weight distribution (Mw/Mn 1.1), and {Mn} directly proportional to monomer conversion. For both vinyloxyethyl monomers, the addition of a new feed of monomer to a polymerization mixture led to an increase in polymer molecular weight which was again proportional to the conversion.     

The effect of continuous slow monomer addition technique on cationic polymerization in liquid sulfur dioxide

Summary The polymerizations of styrene and alpha-methylstyrene in liquid sulfur dioxide have been investigated by the use of the slow, continuous monomer addition technique in the presence of m-chloroperbenzoic acid or CF₃SO₃H as initiator. Quasiliving polymerization has been obtained in Sty/MCPBA/–40°C/liquid SO₂ system. The formed polymer is insoluble in the medium indicating that in liquid SO₂ the propagating species remain active even in a heterogeneous system.     

Tensile and impact strengths of steel fiber reinforced polymer impregnated concrete

Ordinary concrete was reinforced by (i) steel fiber, (ii) polymer impregnation, and (iii) by both steel fiber and polymer impregnation. The tensile strength of concrete was increased 2.62 times by steel fiber reinforcement, 5.56 times by polymer impregnation, and 7.52 times by the combined technique. The increase in impact strength for these three cases were 2–3, 7–15, and 9–15 times respectively, over the plain concrete. Polymer loading was increased from 7% to 9.5% by pressure impregnation at 15 atm. Then the tensile strength of the steel fiber reinforced and polymer impregnated concrete was increased by 8.5 times and the impact strength by 12–28 times.     

Anti-bredt monomers

Summary 1-Aza-6-oxabicyclo [3.2.1]octan-7-one 3 polymerized in bulk to polyurethane at 112–131°C with opening of the 5-membered urethane ring. Organometallic, cationic, anionic and organophosphoric initiators polymerized the strained bicyclic urethane to the polyurethane. In solution the monomer was shown to polymerize slowly under the influence of phosphoric acid. The driving force for the polymerization may be the relief of strain energy in the monomer caused by a boat conformation of the 6-membered ring.     

Synthesis of Semicyclic/Exocyclic Amino-1,3-dienes by organocuprate addition to semicyclic propyniminium salts

Conjugate addition of organocuprates to the 2-ethynyl-substituted cyclic iminium triflates 3 generates aminoallenes which tautomerize immediately to semicyclic 2-amino-1,3-dienes ( 6 , 8 ) or exocyclic 1-amino-1,3-dienes ( 9 , 10 ) with the enamine function incorporated into or attached to a 5-, 6-, or 7-membered ring. In those cases where tautomeric equilibria between the two aminodiene species are possible, the five-membered ring exists virtually exclusively with an exocyclic enamine double bond, but the six-membered ring prefers the exocyclic form. The seven-membered ring can accomodate both forms quite well.     

New dyestuffs for synthetic fibres,benzimidazo-thioxantheno-isoquinolin-ones

Condensation of 3- and 4-bromo- or nitro-7H-benzimidazo[2,1-α]benz[d,e]isoquinolin-7-ones with 2-aminobenzenethiol, followed by Pschorr cyclisation of the resultant product, afforded the isomer mixture of the new heterocycles benzimidazo[1,2-b]thioxantheno[2,1,9-d,e,f,]isoquinolin-7-one and benzimidazo[2,1-a]thioxantheno[2,1,9-d,e,f,]isoquinolin-8-one. Separation of these isomers and their characterisation by unambiguous synthesis is reported. Small amounts of analogous 5-membered sulphur heterocycles were also formed by cyclisation in the β-position of the naphthalene ring. These new heterocycles dye synthetic fibres in fluorescent orange and yellow shades, showing excellent fastness to light and sublimation. Principal mass spectra features of the compounds are given.     

Die Nitril-Carboxamid-Umlagerung

The Nitrile Carboxamide Rearrangement By reaction of cyclohexanone-2-carboxamide ( 4 ) with cyan amide 1-cyano-cyclohex-1-en-2-yl-urea ( 6 ) is formed via nitrile carboxamide rearrangement. Whilst compound 6 with 1,2-diaminobenzene hydrochloride forms 11-amino-1 H-2,3,4,5-tetrahydrodibenzo[b,e][1,4]diazepin hydrochloride ( 8 and 8a ), compound 6 and 1,2-diaminobenzene form hexahydro-benzimidazo[1,2-c]-quinazolin-6-one ( 12 ). Compound 8 with sodium hydroxide yields 11-amino-1 H-2,3,4,11a-tetrahydrodibenzo[b,e]-[1,4]diazepin ( 9 ). Compound 6 reacts with cyclohexylamine to form N-(1-cyanocyclohex-1-en-2-yl)-N′-cyclohexyl urea ( 10 ). Compound 10 with 1,4- or 1,2-diaminobenzene hydrochloride yields compound 7 and 8 . In alkaline solution 10 cyclises to 4-amino-3-cyclohexyl-2,3,5,6,7,8-hexahydroquinazolin-2-one ( 11 ). Compound 4 and malonitrile form either 3-amino-4-cyano-1,2,5,6,7,8-hexahydro-isoquinol-1-one ( 13 ) or 1-amino-4-cyano-2,3,5,6,7,8-hexahydro-isoquinol-3-one ( 14 ). Compound 13 and alkaline formaldehyde react to cyanooctahydroisoquinoline-[2,3-c] [1,3,5]oxdiazin-6-one ( 17 ). 2-Cyanoethyl-cyclohexan-one-2-carboxamide ( 22 ), prepared by Michael-reaction from 4 and acrylonitrile, forms via nitrile carboxamide rearrangement 10-cyano-1,2,3,4,5,6,7,10-octahydroquinolin-2-one ( 24 ) and 2-(1′-cyano-cyclohexyl-2′-one)-propionic acid ( 25 ). Nucleophilic attack of the NH₂-group at the cyanogroup of compound 22 forms 5-(spirocyclohexan-2′-one)-hexahydropyridin-2,6-dione ( 27 ).     

Bio-Guided Isolation of the Cytotoxic Terpenoids from the Roots of Euphorbia kansui against Human Normal Cell Lines L-O2 and GES-1

The dried roots of Euphorbia kansui (kansui) have been used for centuries in China as a herbal medicine for edema, ascites, and asthma. The 95% ethanol extract showed a significant inhibition of cell proliferation against human normal cell lines L-O2 and GES-1. Bioassay-guided separation of the 95% ethanol extract from the roots of E. kansui led to the isolation of 12 diverse terpenoids whose structures were identified by ¹H, ¹³C NMR spectroscopy and ESI-MS as kansuinine A (1), kansuinine B (2), kansuinine C (3), kansuiphorin C (4), 3-O-(2′E,4′Z-decadienoyl)-20-O-acetylingenol (5), 3-O-(2′E,4′Edecadienoyl)-20-O-acetylingenol (6), 3-O-(2′E,4′Z-decadienoyl)-20-deoxyingenol (7), 3-O-benzoyl-20-deoxyingenol (8), 5-O-benzoyl-20-deoxyingenol (9), kansenone (10), epi-kansenone (11), euphol (12). All these 12 terpernoids were evaluated in vitro for cytotoxicity on L-O2 and GES-1 cell lines. Most ingenane-type diterpenoids and 8-ene-7-one triterpenoids (5–11) exhibited a relatively lower IC₅₀ value; therefore, these compounds had stronger cytotoxicity against human normal cell lines L-O2 and GES-1 with dose-dependent relationships. These results will be significantly helpful to reveal the mechanism of toxicity of kansui and to effectively guide safer clinical application of this herb.     

Cyclo-depolymerization of olefin-containing polymers to give macrocyclic oligomers by metathesis and the entropically-driven ROMP of the olefin-containing macrocyclic esters

A range of olefin-containing polyesters were prepared by acyclic diene metathesis (ADMET) and were then subjected to cyclo-depolymerization (CDP). CDP involves metathesis of the 1,2-disubstituted olefinic linkages and gives a homologous family of strainless macrocyclic oligomers (MCOs). When Grubbs' “first generation” catalyst was used at 23 °C the CDPs were sluggish and required reaction times of several days, but with the “second generation” Grubbs' catalyst at 40 °C CDPs were complete in only 2-4 h. Macrocyclic olefin-containing lactones were also prepared by ring-closing metathesis. Under appropriate reaction conditions (i.e. neat cyclics or very concentrated solutions of cyclics) the strainless macrocycles successfully underwent ring-opening metathesis polymerizations (ROMPs). Unlike most ROMPs reported in the literature, which are usually enthalpically-driven, these ROMPs are entropically-driven (ED-ROMPs). The results obtained clearly demonstrate that 21-, 24-, 27-, 28-, 38-, 45-, 52-, 63-, 64-, 68- and 84-membered macrocycles polymerized successfully. Two of the ED-ROMPs were carried out in films. These ROMPs appeared to proceed in part in the solid phase, i.e. were examples of solid state polymerization.     

Asymmetrisch katalysierte Additionen von Thiolen an α-Aminoacrylsäure- Derivate und Nitroolefine

Asymmetrically Catalyzed Additions of Thiols to Derivatives of α-Aminoacrylic Acid and Nitroolefins Benzylmercaptane and other thiols were asymmetrically added, under the catalytic influence of optically active bases (preferently cinchona alkaloids), to the double bond of methyl α-phthalimidoacrylate or 2-ethyl-4-methylene-1,3-oxazolin-5-one to give optically active derivatives of cysteine in optical yields upto 54%. Similar asymmetric additions of SH-compounds were performed also with 2-nitrostyrene and 1-phenyl-2-nitropropene.     

烟熏腊鸡肉的挥发性化学成分

用氮气冲洗、Sep PakC18固相萃取柱吸附和冷有机溶剂捕集提取烟熏腊鸡肉的挥发性成分,用色谱-质谱联用法测定结构,用气相色谱(FID检测器)法进行定量分析。结果表明,烟熏腊鸡肉的主要香气成分为11个酚及其衍生物,以及N 异丙基甲亚磺酰氨基 2 环己烯 2 酮、5 甲基 4 异丙烯基 4 己烯醛、4,6 二甲基 3 苯甲烯氨基 2 (1H)吡啶酮、3 (2,2 二甲基亚丙基)二环[3,3,1]壬烷 2,4 二酮、2,6 二叔丁基 4 羟基 4 甲基 2,5 环己二烯 1 酮、2,6 二叔丁基 4 亚甲基 2,5 环己二烯 1 酮、二苯胺、十八醛、6 甲氧基 1 吲哚 2 基 3,4 二氢 β 咔啉和2,5 二苯基 3 (2 糠酰)吡咯,其中酚及其衍生物主要提供烟熏香,烟熏腊鸡肉的挥发性成分与新鲜鸡肉的挥发性成分是不同的。     

Surfactant-mediated synthesis of metal substituted hexaaluminate from alumina sol

Manganese substituted hexaaluminate has been prepared using environmentally benign surfactants such as Triton X-100, under ambient condition with a commercial alumina sol and metal acetate precursors. The surface area of the pure alumina can be controlled to 10–70 m² g⁻¹ using cetyltrimethylammonium chloride after heating in oxygen flow at 1200°C for 6 h. The crystal structure of the obtained alumina was high purity θ-Al₂O₃. Incorporation of La and Mn leads to the formation of the high purity manganese substituted hexaaluminate with a surface area of 30–40 m² g⁻¹ which is also controllable using organic additives such as urea. The catalytic activity of the manganese substituted hexaaluminate was comparable to the sol–gel derived hexaaluminate catalyst from metal alkoxides.