3-邻氯苯基-3-(5,5二甲基-3-羟基-2-环己烯-1-酮-2-基)丙酸乙酯的合成和晶体结构

标题化合物C19H23O4Cl（4）是由邻氯苯甲醛（1）与5，5-二甲基-1，3-环己二酮（2）、2，2-二甲基-1，3-二氧六环-4，6-二酮（3）在乙醇中反应而得。结构通过单晶X-射线衍射分析确定，其晶体属于单斜晶系，空间群晶体结构用直接法解出，使用全矩阵最小二乘法对原子参数进行修正，最后的偏离因子R＝0．034，Rw＝0．042。在晶体结构中存在一个共轭的烯醇结构。单晶X-射线分析表明；平面1（C（1）～C（6）、Cl）和平面2（C（8）～C（10）、C（12）、C（13））之间的两面角为97．11°，原子C（7）呈变形的四面体构型。     

3,4-己二酮的合成

3,4-己二酮是一种黄色油状液体,具有奶油似香味,熔点-10℃,沸点130℃,它本身可作为香料广泛应用于软饮料、冰冻食品、糖果、胶冻、布丁等食品中,已被列入美国食品香料与萃取物制造协会制订的“一般认为安全”食品香料列表中[1],使用限量为10.0mg/kg。此外,它还可以作为反应中间     

3-取代苯基-3-三氯锗基丙酸的合成

作者曾综述过某些有机锗化合物具有广谱药理活性,并报道了有机锗倍半氧化物,及有机锗的倍半硫化物的合成。已发表的专利证明其中一大类具有生物活性的有机锗化合物具有抗癌活性,放射增敏作用,杀菌作用,酶分解抑制作用等。而这类化合物的合成均经过3-三氯锗基丙酸中间体。本文用三氯锗烷与取代肉桂酸反应,合成了尚未见报道的新化合物,3-取代苯基-3-三氯锗基丙酸活性中间体1～14。它的合成为一系列不同种类具有生物活性的有机锗化合物的开发研究提供了重要的中间体。     

n-(4,6-二取代嘧啶-2-基)-2-(2,4-二氯苯氧基)丙酰胺衍生物的合成及除草活性

二氯苯氧丙酸;嘧啶;酰胺;合成;除草活性     

Synthesis of （S）-2-（3-Arylacrylamido）-3-{4-[2-（5-methyl-2-phenyloxazol-4-yl）ethoxy]phenyl}propanoic Acids

The synthesis of （S）-2-（3-arylacrylamido）-3-{4-[2-（5-methyl-2-phenyloxazol-4-yl）etho- xy]phenyl}propanoic acids is described. Their structures were confirmed by ^1H-NMR.     

β-(3,4-二羟基苯基)-α-羟基丙酸异丙酯/冰片酯合成研究

以3,4-二羟基苯甲醛为起始原料, 经苄基保护、Darzens环氧化、Lewis酸开环、NaBH4还原、催化加氢脱保护得到β-(3,4-二羟基苯基)-α-羟基丙酸异丙酯和β-(3,4-二羟基苯基)-α-羟基丙酸冰片酯, 所得化合物的结构通过1H NMR、13C NMR, IR, MS证实. 该方法操作简单、毒性低、产物易于纯化.     

4-异丁酰基庚二酸及3,3-二氰乙基-2,4-己二酮的环合反应

等由酮的一氰乙基化产物水解后得到的δ-酮酸,在大量乙酐或者乙酰氯存在下合成了不饱和δ-内酯.我们用4-异丁酰基庚二酸(1)在过量醋酸酐及乙酰氯存在下回流5h得到7-氧代-8,8-二甲基-△~9-六氢香豆素(2).     

阴离子型聚氨酯水乳液的合成I.2,2-二羟甲基丙酸与2,6-甲苯二异氰酸酯反应动力学研究

采用二正丁胺法及ＦＴＩＲ法研究了合成阴离子型聚氨酯水乳液的核心反应，２，２－二羟甲基丙酸与２，６－甲苯二异氰酸酯的反应动力学，获得了相关的反应活化能工提出了反应动力学模型。     

二羟甲基丙酸合成工艺研究

二羟甲基丙酸因其独特的结构ＣＨ３Ｃ（ＣＨ２ＯＨ）２ＣＯＯＨ,它是目前比较理想的一种亲水单体。由它制备的水性聚氨酯比国内用酒石酸等法合成的产品在贮存稳定性方面,有较大提高［１］。为此,本工作进行了二羟甲基丙酸的合成工艺研究。１实验部分１．１主要试剂与仪...     

2-取代芳基-4-丙酸乙酯基-1,5-苯并二氮卓衍生物的高效合成

以取代的芳香醛和乙酰丙酸乙酯为原料,通过克诺维纳盖尔(Knoevenagel)缩合、亲核加成、环合、脱水等过程,快速高效地合成了8种未见文献报道的2-芳基-4-丙酸乙酯基-1,5-苯并二氮杂卓化合物.通过₁H NMR、₁₃C NMR、IR、MS和单晶衍射确定了其目标产物结构,对合成目标化合物的反应条件进行了较详细的研究,并提出了可能的反应机理。     

Differential rates of reversibility of ecteinascidin 743-DNA covalent adducts from different sequences lead to migration to favored bonding sites.

Ecteinascidin 743 (Et 743), one of a series of structurally related antitumor antibiotics isolated from a marine tunicate, is currently in phase II clinical trials. Et 743 alkylates guanine N2 through the minor groove of DNA. Hydrogen-bonding networks that associate the drug with a three base pair DNA recognition site have been proposed to contribute to both the reactivity and the stability of the Et 743-DNA adduct. Here, we report that the reaction of Et 743 with DNA is reversible under nondenaturing conditions and that the rate of this reverse reaction depends critically upon the DNA-modified sequence. Quite unexpectedly, it was found that although the rates of alkylation are similar for the 5'-AGT and 5'-AGC sequences, reversal from the 5'-AGT sequence occurs faster than from the 5'-AGC sequence. Consequently, it is the differences in the rate of the reverse reaction that dictate the sequence selectivity of Et 743 toward its favored target sequence. As a direct consequence of the reversible nature of Et 743 with DNA, Et 743 can migrate from the nonfavored bonding sequence (e.g., 5'-AGT) to the favored DNA target site (e.g., 5'-AGC). The data suggest that the observed differences in the rate of reversibility arise from differences in the stability of the Et 743-DNA adduct at the 5'-AGT and 5'-AGC target sequences. On the basis of gel electrophoresis and (1)H NMR experiments, the Et 743-AGT adduct is less stable, has more dynamic motion, and produces different conformational changes in the DNA than the more stable Et 743-AGC adduct. The shuffling of Et 743-DNA adducts to the more stable alkylation sites has important implications for understanding the underlying relationship between the structural modification of DNA by Et 743 and its biological potency and efficacy in tumor cells.     

Synthesis, spectroscopic and structural characterization of tertiary phosphine tellurium dihalides Et3PTeX2(X = Cl, Br, I)

The reactions of triethylphosphine telluride with SO2Cl2 or I2 produced the first structurally characterized tellurium-containing tertiary phosphine chalcogen dihalides, Et3PTeCl2 and Et3PTeI2, respectively, in good yields. The corresponding dibromide, Et3PTeBr2, was obtained by an in situ reaction between Et3PTeCl2 and two equivalents of Me3SiBr. This series of compounds has been characterized in the solid state by X-ray structural analyses and in solution by multinuclear NMR spectra. The structures of Et3PTeX2(X = Cl, Br, I) all show a T-shaped geometry around tellurium with weak Te...halogen interactions giving rise to centrosymmetric dimers. NMR data indicate that Et3PTeI2 exhibits the weakest P-Te bond in solution. The ionic complexes, [(Et3PO)2H]2[Te2I6] and [(Et3PO)2H]2[TeI4], were isolated from THF solutions of Et3PTeI2 and characterized by X-ray structural determinations.     

Charge-transfer photochemistry of the ternary complex (dithio-diseleno-carbamato)copper(II)

Photolysis of the ternary system consisting of diethyldithiocarbamate (Et2dtc), diethyldiselenocarbamate (Et2dsc) and copper(II) (1:1:1) has been studied in isobutylmethylketone (IBMK), toluene, chloromethane and chloromethane/ROH solutions (chloromethane = CCl4, CHCl3 or CH2Cl2 and ROH = EtOH or i-PrOH). The results obtained by EPR techniques and UV-Vis data indicate that a homolytic Cu-S bond cleavage involving the dithiocarbamate (dtc) ligand appears as the primary photo-process in Cu(Et2dtc)(Et2dsc) photolysis. Further conversion of the primary photoproduct Cu(I)(Et2dsc) is discussed in terms of a specific interaction with the solvent. In chloromethanes and chloromethane/ROH Cu(I)(Et2dsc) is oxidised by the solvent to give the corresponding paramagnetic mixed-ligand Cu(II)(Et2dsc)Cl complex and/or its chloride-bridged and EPR silent dimer Cu2(Et2dsc)2Cl2. The formation of the monomeric species occurs through a co-ordination of the alcohol molecule in the xy plane of the complex. Because of its co-ordination inertness, toluene poorly stabilises the primary photoproduct Cu(I)(Et2dsc), thus providing an effective primary recombination process and lower efficiency of Cu(Et2dtc)(Et2dsc) photolysis. The formation of the bis-solvated mixed-ligand complex Cu(II)(Et2dsc)+ in IBMK is also discussed.     

Reactions of Et(3)ZnLi with ketones: electronic and steric effects(1)

Toluene solutions of composition Et(3)ZnLi react rapidly with aldehydes and ketones to form addition products. Et(3)ZnNa and Et(3)ZnK solutions react readily with the same substrates although metalation, as well as addition, is significant with substrates having alpha-hydrogens. The Et(3)ZnM solutions react with 2-cyclohexenone to give mainly the 1,4-addition product. Relative rates of addition of Et(3)ZnLi to substituted acetophenones give a Hammett rho of 2.78. Addition of Et(3)ZnLi to acetophenone is slowed significantly by alpha and ortho methyl substituents; relative rates of addition to acetophenone, o-methylacetophenone, and tert-butyl phenyl ketone are 1.00, 0.012, and 0.003.     

Preparation of mononuclear tungsten tris(sulfido) and molybdenum sulfido-tetrasulfido complexes with hydridotris(pyrazolyl)borate coligand and conversion of the former into sulfido-bridged bimetallic complex having Pt(mu-S)2WS core

Treatment of [Et4N][(Me2Tp)W(CO)3] (Me2Tp = HB(3,5-dimethylpyrazol-1-yl)3) with S8 in DMF at room temperature afforded a tris(sulfido) complex [Et4N][(Me2Tp)WS3] (1a), while that of [Et4N][TpW(CO)3] (Tp = HB(pyrazol-1-yl)3) in MeCN resulted in the formation of [Et4N][TpWS3] (1b) along with [Et4N]2[[WO(S2)2]2(mu-S)] (6) as a byproduct. Under similar conditions, [Et4N][(Me2Tp)Mo(CO)3] gave a mixture of a sulfido-tetrasulfido complex [Et4N][(Me2Tp)MoS(S4)] (2a) and its monooxo analogue [Et4N][(Me2Tp)MoO(S4)], although a sulfido-tetrasulfido complex [Et4N][TpMoS(S4)] (2b) was exclusively obtained from [Et4N][TpMo(CO)3]. The reaction of 1a with [PtCl2(cod)] (cod = 1,5-cyclooctadiene) in MeCN at room temperature led to the formation of a sulfido-bridged mixed-metal complex [Et4N][(Me2Tp)WS(mu-S)2PtCl2] (10). The structures of new complexes have been determined in detail by the X-ray analyses for 1a.MeCN, 1b, 2a, 2b, 6, and 10.     

Visualization of distribution of endotoxin trapped in an endotoxin-blocking filtration membrane

Since the finding of β₂-microglobulin as a causal substance in the carpal tunnel syndrome of chronic hemodialysis patients, removal of β₂-microglobulin has been performed using highly permeable dialysis membranes with larger pores. Such large-pore membranes tend to allow endotoxins (Et), harmful substances contained in dialysate, to enter blood. At present, as a countermeasure, Et-blocking filtration membranes are used to remove Et from dialysate. However, Et removal mechanism by these membranes has not been clarified yet. The objective of this study is thus to visualize distribution of fluorescence-labeled Et trapped inside the polyester–polymer alloy (PEPA) membrane, a widely used Et-blocking filtration membrane using a confocal laser scanning fluorescence microscope (CLSFM). Et were observed mainly in the outer skin layer of the hollow fiber, while some in the void and inner skin layers. No Et were present inside the hollow fiber. In conclusion, we succeeded in visualization of Et distribution inside the Et-blocking filtration membrane using CLSFM. This novel visualization technique may allow evaluation of distribution of Et trapped inside various kinds of Et-blocking filtration membranes.     

Photoreactivity of crystals of a rhodium dithionite complex with ethyltetramethylcyclopentadienyl ligands: crystal surface morphology changes and degradation

A photoreactive rhodium dithionite complex [(RhCp(Et))(2)(μ-CH(2))(2)(μ-O(2)SSO(2))] (1(Et)) with Cp(Et) (η(5)-C(5)Me(4)Et) ligands was newly synthesized. Upon short-time irradiation with low intensity light, two kinds of stepwise surface morphology changes of the crystal 1(Et) were observed. Prolonged irradiation with high intensity light caused cracking and breaking down of the crystal.     

Photochemistry of dithiocarbamate Cu(II) complex in CCl4

Laser pulse photolysis was used to study the nature and reactions of intermediates in the photochemistry of the flat dithiocarbamate complex Cu(Et(2)dtc)(2) in CCl(4). A nanosecond laser pulse (355 nm) is shown to induce intermediate absorption bands of bivalent copper complex whose coordination sphere contains a dithiocarbamate radical Et(2)dtc(?) and a chloride ion at the axial position ([(Et(2)dtc)Cu(Et(2)dtc(?))Cl(a)]). At room temperature during some microseconds after the laser pulse, this intermediate interacts with the initial complex to form presumably a dimer [Cu(2)(Et(2)dtc)(3)(Et(2)dtc(?))Cl]. The latter vanishes in the second-order reaction. Analysis of kinetic and spectral features gives the arguments for the formation of a cluster [Cu(2)(Et(2)dtc)(3)Cl-tds-Cu(2)(Et(2)dtc)(3)Cl], which produces a new absorption band at 345 nm. The cluster decomposes in ～5 ms into final products, a binuclear complex [Cu(2)(Et(2)dtc)(3)Cl] and tetraethylthiuramdisulfide (Et(4)tds).     

A kinetic study of reactions of Et3ZnLi and di-tert-butyl ketone

An organozincate of composition Et3ZnLi and di-tert-butyl ketone react in toluene to form (after hydrolysis) ethyl-di-tert-butylmethanol. The rate is proportional to approximately [Et3ZnLi](-0.5)[ketone](1) when the initial concentration of Et3ZnLi is greater than that of the ketone but proportional to [Et3ZnLi](1)[ketone](-1) when the initial concentration of ketone is greater than that of Et3ZnLi. The rate of addition of Et3ZnK to di-tert-butyl ketone is <10(-4) that of Et3ZnLi.     

Estimating the limiting reducing power of SmI2/H2O/amine and YbI2/H2O/amine by efficient reduction of unsaturated hydrocarbons

The mixture of samarium diiodide, amine, and water (SmI2/H2O/Et3N) is known to be a particularly powerful reductant, but until now the limiting reducing power has not been determined. A series of unsaturated hydrocarbons with varying half-wave reduction potentials (E(1/2) = -1.6 to -3.4 V, vs SCE) have been treated with SmI2/H2O/Et3N and YbI2/H2O/Et3N, respectively. All hydrocarbons with potentials of -2.8 V or more positive were readily reduced with SmI2/H2O/Et3N, whereas all hydrocarbons with potentials of -2.3 V or more positive were readily reduced using YbI2/H2O/Et3N. This defines limiting values of the chemical reducing power of SmI2/H2O/Et3N to -2.8 V and of YbI2/H2O/Et3N to -2.3 V vs SCE.