L-硒代蛋氨酸的合成及工艺优化

将蛋氨酸（I）烷基化后再经过溴取代反应生成溴代高丝氨酸溴酸盐（III）；接着将硒分别和三种还原剂反应得到二硒化二钠后与化合物III反应；得到的硒代高胱氨酸（IV）经由三乙酰氧基硼氢化钠还原、碘甲烷甲基化获得硒代蛋氨酸（V）。对其主要步骤进行优化筛选，获得最优的合成工艺条件：采用新型还原剂三乙酰氧基硼氢化钠制备二硒化二钠可以获得的中间产物IV收率较高，而且当氢氧化钠与三乙酰氧基硼氢化钠摩尔比为4.0：1.0时，化合物III的最高产率为62.42%；采用化合物IV、碘甲烷摩尔比1.0：2.0，以及氢氧化钠与三乙酰氧基硼氢化钠的摩尔比2.7：1.0，可获得终产物V的最高产率为75.79%；最终产物V的结构结晶纯化（纯度95%）后结合质谱、氢谱、碳谱进行确证。     

含环己烯结构新型氯代双酮化合物的合成及表征

本文以顺丁烯二酸酐、氯苯经Ｆｒｉｅｄｌｌｅ－Ｃｒａｆｔｓ反应合成了１,２－二（４－氯苯甲酰基）乙烯。经Ｄｉｅｌｓ－Ａｌｄｅｒ反应,以异戊二烯环加成合成了含环乙烯结构的双氯双酮化合物：１－甲基－４,５－二（４－氯苯甲酰基）环己烯。该氯代双酮化合物具有不饱和双键结构,是制备聚芳醚酮功能高分子材料的理想单体。     

一种新型β-二酮化合物的合成及结构表征

通过Claisen缩合反应,在强碱叔丁醇钾的作用下,把长链端烯引入到β-二酮分子中,合成了一种新型的含长链端烯的β-二酮化合物——13-十四碳烯-2,4-二酮(BSH),并通过红外光谱、核磁共振、质谱和元素分析对其结构进行了确证。这种β-二酮化合物在氯仿溶液中主要以烯醇形式存在。该化合物可作为配体用于有机电致发光配合物的合成。     

含吡啶基的HBC衍生物的合成

以四芳基取代环戊二烯酮2与二烷基取代的二苯乙炔3通过Diels-Alder环加成反应得到六芳基取代苯4。化合物4在路易斯酸催化下通过Scholl环氧化脱氢反应,生成化合物5,5再与4-硼酸吡啶发生Suzuki偶联反应生成目标化合物1。     

6,11-烷基-5,12-萘并萘二酮的合成与反应机理

以邻苯二甲酸酐和丁二酸为起始原料,经多步反应得到了一系列新的6,11-烷基-5,12-萘并萘二酮化合物。它们的结构通过红外光谱、核磁共振氢谱、碳谱、质谱表征。提出了6,11-羟基-5,12-萘并萘二酮(3)与格氏试剂可能的反应机理。该合成反应机理的主要特点是格氏试剂与6,11-羟基-5,12-萘并萘二酮化合物发生了亲核加成反应,随后发生消去水的消除反应。     

苄氧基苄基噁唑酮类手性诱导试剂的合成研究

以N-Boc-L-酪氨酸乙酯为原料,经过酚羟基保护、酯基还原、氨基脱保护得到氨基醇,利用N,N-二甲基甲酰胺乙缩醛制备噁唑啉环,在氨基锂作用下,与硒(硫)作用分别得到(4S)-4-(4′-苄氧基)苄基-噁唑-2-硒酮和(4S)-4-(4′-苄氧基)苄基-噁唑-2-硫酮手性助剂,总产率分别为39.2%和37.9%。运用IR1、HNMR、13CNMR和元素分析等方法进行了表征,所得结果与化合物结构相符合。     

二硒醚的合成进展

综述了重要的有机合成试剂二硒醚的合成方法,并指出其优缺点。提出了用羰基化合物为原料制备二硒醚是很有发展前景的一种方法。     

3-[4-(甲基磺酰基)-2-氯苯甲酰基]双环[3.2.1]辛烷-2,4-二酮的合成研究

标题化合物是合成稻田除草剂的中间体,以降冰片烯为原料,经二氯卡宾的加成、扩环反应和水解反应生成3-氯双环[3.2.1]-3-辛烯-2-醇;随后烯丙醇氧化制得α,β-不饱和酮;接着在氰化钾催化剂的作用下和氢氧化钠反应,得到双环[3.2.1]辛烷-2,4-二酮;最后再发生酰基化反应得到标题化合物。化合物结构用1HNMR、13CNMR表征,纯度用HPLC确定。     

固相合成硒芳香杂环化合物

在室温下,分别由不同分子结构的芳香邻二胺与二氧化硒通过固相反应合成了2,1,3-苯并[c]硒二唑(BS)、5-甲基-2,1,3-苯并[3,4-c]硒二唑(MB)、2,1,3-萘并[2,3-c]硒二唑(NS)和7-羟基-1,2,5-硒二唑并[3,4-d]嘧啶(HSP)等硒杂环化合物。反应产率分别为BS：77．1％、MB：73．5％、NS：76．7％、HSP：50．5％;用红外吸收光谱(IR)和X-射线粉末衍射(XRD)对反应过程及产物进行监测和表征,并与液相反应合成的产物进行了对比;还用元素分析(EA)、感应耦合等离子体(ICP)分析化合物的元素组成。     

2-苯基-1,2-苯并异硒唑-3-(2H)-酮的合成研究

在N2保护下,采用水合肼的碱性水溶液还原硒粉制备了K2Se2,不经分离直接与邻氨基苯甲酸的重氮盐反应得到了中间体2,2'-二硒化苯甲酸;在环合反应合成2-苯基-1,2-苯并异硒唑-3-(2H)-酮(Ebselen)时改用了乙醚-水为反应体系,K2CO3水溶液作为副产物HCl的吸收剂,促使胺解关环反应顺利进行,产物易分离、纯化得2-苯基-1,2-苯并异硒唑-3-(2H)-酮。     

Oligomere aus gegensinnig angeordneten Chalkon-Bausteinen

The cross-conjugated oligomers 1a – d , which contain up to eight alternately arranged chalcone building blocks, were prepared by stereoselective condensation reactions of formyl and acetyl components. The synthetic sequence started with 1,4-dibromo-2,5-dipropoxybenzene ( 2 ). Bouveault reactions with DMF and DMA yielded the aldehydes 3 and 6 and the ketones 7 and 10 . After the protection of the carbonyl group ( 3 → 4 and 7 → 8 ), a further Bouveault reaction led to monoprotected dialdehyd 5 and diketone 9 , respectively. Repetitive condensation reactions starting with the acetophenone derivative 11 and 5 furnished the aldehyde 12 , the ketone 13 and the aldehyde 14 . In the final step the target compounds 1 were obtained again by condensation reactions: 6 + 11 → 1a , 10 + 12 → 1b , 6 + 13 → 1c , 10 + 14 → 1d . Thus a convergent and coupled synthesis was achieved in order to generate constitutionally and configurationally pure oligochalcones.     

Identification of Polyketides in the Cuticular Waxes of Triticum aestivum cv. Bethlehem

Cuticular waxes are complex mixtures consisting mostly of very‐long‐chain aliphatics with single, primary functional groups. However, the waxes of many plant species also include aliphatics with one or more functional groups residing on subterminal or mid‐chain carbons. In the present work, the cuticular wax mixtures from flag leaf blades and peduncles of Triticum aestivum cv. Bethlehem were analyzed in a search for novel wax constituents with in‐chain functionalities, potentially of polyketide origin. The structures of compounds belonging to six different compound classes were elucidated using gas chromatography–mass spectrometry of various derivatives. Among them, a series of 2,4‐ketols was identified, with odd carbon numbers ranging from C₂₅ to C₃₇ and peaking at C₃₃. The analogous C₃₃ 2,4‐diketone was identified as well, together with a pair of co‐eluting C₃₁ mid‐chain β‐ketol isomers (16‐hydroxyhentriacontan‐14‐one and 14‐hydroxyhentriacontan‐16‐one), a pair of co‐eluting C₃₀ mid‐chain α‐ketol isomers (15‐hydroxytriacontan‐14‐one and 14‐hydroxytriacontan‐15‐one), the corresponding C₃₀ 14,15‐diketone, and a pair of co‐eluting C₃₁ ketones (hentriacontan‐14‐one and hentriacontan‐16‐one). All newly discovered structures contain ketone functional groups, with similar C₁₃H₂₇ and C₁₅H₃₁ alkyl chains on either side of the functionalities, thus resembling the previously reported very‐long‐chain β‐diketones dominating the wheat wax mixtures. Based on these structural characteristics, possible biosynthetic pathways leading to the newly identified polyketide‐like compounds are proposed.     

Synthesis, loading control and preliminary tests of 2,4,6-triphenylpyrylium supported onto Y-zeolite as solar photocatalyst

A heterogeneous photocatalyst has been obtained by hosting the 2,4,6-triphenylpyrylium cation inside the supercages of Y-zeolite. Preparation of the new material has been achieved by means of a formal ion exchange in aqueous medium. Nevertheless, the mechanism is more complex, as bulky 2,4,6-triphenylpyrylium cation is unable to diffuse through the channels of Y-zeolite. The following steps are involved: (a) hydrolytic opening of the pyrylium ion to give a linear diketone; (b) diffusion of the diketone through the channels to reach the supercages; and (c) thermal recyclization under dehydrating conditions. Elemental analysis of the new material was consistent with the pyrylium cation located inside the zeolite. No sulfur was found in the loaded zeolite, indicating that hydrogensulfate is no longer the counter-ion of pyrylium. Accordingly, the stoichiometric amount of Na⁺ was found in the filtered waters recovered after the synthesis. Besides, the IR spectrum of the dry material was coincident with that of 2,4,6-triphenylpyrylium, while the spectrum of a less thoroughly dried sample showed, together with the absorption bands corresponding to pyrylium, other bands assignable to the diketone. Zeolite loading can be controlled in the range of 3–15% of organic carbon. The performance of the new material as a solar photocatalyst for oxidative pollutant degradation was checked using four cinnamic acid derivatives as target compounds. Aqueous solutions (250 mL) of these model pollutants (0.001 M) were irradiated by solar light in the presence of different amounts of solid photocatalyst. Oxidation was efficiently achieved as analysed by HPLC and followed in all cases a pseudo first order kinetics. The most satisfactory results were obtained using 1 g/L of Y-zeolite containing 6% of 2,4,6-triphenylpyrylium cation.     

Methyl ketone-photosensitized polymerization of N-methylolacrylamide with cotton

Photoinitiated, free-radical reactions of cotton cellulose with N-methylolacrylamide (NMA) from aqueous solution through direct excitation of cellulose are reported. Also reactions initiated by energy transfer from excited methyl ketone compounds to cellulose are reported. Dimethyl ketone, dimethyl ketoneformaldehyde, dimethyl diketone, dimethyl diketoneformaldehyde, methyl ethyl ketoneformaldehyde, and methyl phenyl ketoneformaldehyde were used in the sensitized reactions. When methyl ketone products were in solution during photoirradiation, they acted as sensitizers to increase the rate and extent of the reaction of NMA with cotton cellulose. When products that contained formaldehyde were covalently reacted with cotton before photoirradiation, the rate and extent of the reaction of NMA with cellulose were generally decreased. These effects can be at least partially explained by intramolecular energy transfer, as determined by chemiluminescence, electron spin resonance, and excitation fluorescence measurements. When methyl phenyl ketoneformaldehyde was covalently linked to cellulose before photoirradiation, energy localization that initiated free-radical polymerization of NMA was minimized. When cellulose that was padded with a monomer solution was dried before photoirradiation, the extent of the reaction of NMA with cellulose was decreased.     

Inactivation of glucosamine-6-phosphate synthase by N3-oxoacyl derivatives of L-2,3-diaminopropanoic acid

N(3)-Oxoacyl derivatives of L-2,3-diaminopropanoic acid 1-4, containing either an epoxide group or a conjugated double bond system, inactivate Saccharomyces cerevisiae glucosamine-6-phosphate (GlcN-6-P) synthase in a time- and concentration dependent manner. The results of kinetics studies on inactivation suggested a biphasic course, with formation of the enzyme-ligand complex preceding irreversible modification of the enzyme. The examined compounds differed markedly in their affinity to the enzyme active site. Inhibitors containing a phenyl ketone moiety bound much more strongly than their methyl ketone counterparts. The molecular mechanism of enzyme inactivation by phenyl ketone compounds 1 and 3 was elucidated by using a stepwise approach with 2D NMR, MS and UV-visible spectroscopy. A substituted thiazine derivative was identified as the final product of a model reaction between an epoxide compound, 1, and L-cysteine ethyl ester (CEE); and the respective cyclic product, found as a result of reaction between 1 and CGIF tetrapeptide, was identical to the N-terminal fragment of GlcN-6-P synthase. On the other hand, the reaction of a double-bond-containing compound, 3, with CEE, CGIF and GlcN-6-P synthase led to the formation of a C-S bond, without any further conversion or rearrangement. Molecular mechanisms of the reactions studied are proposed.     

Synthesis and characterization of organo‐soluble poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains

Poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains were synthesized by polycondensation of each of the two bisphenol monomers viz, 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane and 1,1‐bis(4‐hydroxyphenyl)‐3‐pentadecyl cyclohexane with activated aromatic dihalides namely, 4,4′‐difluorobenzophenone, and 1,3‐bis(4‐fluorobenzoyl)benzene in a solvent mixture of N,N‐dimethylacetamide and toluene, in the presence of anhydrous potassium carbonate. Polymers were isolated as white fibrous materials with inherent viscosities and number average molecular weights in the range 0.70–1.27 dL g^?1 and 76,620–1,36,720, respectively. Poly(ether ether ketone)s and poly(ether ether ketone ketone)s were found to be soluble at room temperature in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, and pyridine and could be cast into tough, transparent, and flexible films from their solutions in chloroform. Wide angle X‐ray diffraction patterns exhibited a broad halo at around 2θ = ～ 19° indicating that the polymers containing pentadecyl chains were amorphous in nature. In the small‐angle region, diffuse reflections of a typically layered structures resulting from the packing of pentadecyl side chains were observed. The temperature at 10% weight loss, obtained from TG curves, for poly(ether ether ketone)s and poly(ether ether ketone ketone)s were in the range 416–459°C, indicating their good thermal stability. A substantial drop in glass transition temperatures (68–78°C) was observed for poly(ether ether ketone)s and poly(ether ether ketone ketone)s due to “internal plasticization” effect of flexible pendant pentadecyl chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Reduction of fatty ester Δ2-isoxazoline heterocycles. Preparation of fatty esters containing the β-hydroxy ketone moietyheterocycles. Preparation of fatty esters containing the β-hydroxy ketone moiety

Fatty ester compounds containing the β-hydroxy ketone moiety were prepared in good yields from their corresponding fatty Δ²-isoxazoline heterocyclic precursors by a reductive hydrogenolysis-hydrolysis procedure using Raney nickel as catalyst. By this methodology, C-17, C-18, and C-19 straight-chain fatty methyl esters containing the 10-hydroxy 12-keto moieties were prepared in 73, 83, and 92%, respectively, from their corresponding isoxazoline fatty ester compounds. Two other 10-hydroxy 12-keto C-12 and C-14 fatty ester compounds were prepared in 84 and 92% yield, respectively. The C-12 β-hydroxy ketone contains a phenyl ring at C-12, whereas the C-14 β-hydroxy ketone compound has two methyl substituents at C-13. GC-MS using electron impact ionization was used to determine the hydroxyl and ketone positions after conversion of the hydroxyl group into its corresponding trimethylsilyl ether. The precursor fatty ester Δ²-isoxazolines used in this study are readily available in one step from a 1,3-dipolar cycloaddition reaction between nitrile oxides and methyl 10-undecenoate. This overall two-step sequence, 1,3-dipolar cycloaddition followed by reductive ring opening, represent a convenient method to construct fatty ester compounds in good yields containing the β-hydroxy ketone functionality, an outcome not easily accessible by other methods.     

Analysis of products of high-temperature pyrolysis of various hydrocarbons

Ethane, ethylene, acetylene, propane and neopentane have been pyrolyzed at 1173 K, and methane at 1372 K in a flow system, and the volatile pyrolysis products analyzed. Eleven aromatic hydrocarbons, containing 14 or fewer carbon atoms, accounted for 98 + % of the liquid products recovered in each case. Benzene was the main product, followed by naphthalene. No compounds with branched chains or multiple substituents were present, and compounds containing even numbers of carbons comprised 93–99% of each mixture. Acetylene was a major component of the gaseous effluent from each of the initial hydrocarbons. The effect of temperature on the composition of the gaseous effluent during pyrolysis of methane, ethane and ethylene was determined. Carbon film deposition from methane commenced at about 1273 K; from ethane at 1015 K and from ethylene at 1100 K, in each instance coinciding with the appearance of acetylene in the effluent. As the temperature was raised, at first the increase in the rate of carbon deposition closely followed the increase in the concentration of acetylene in the effluent. It is proposed that acetylene may be a common factor in the pyrolysis of aliphatic hydrocarbons, perhaps acting as the precursor of both surface carbon and aromatic hydrocarbons by a process of head-to-tail linkage of two-carbon units at active surface sites to form chains that then undergo dehydrogenation to carbon or cyclization and desorption as aromatic species.     

Au(III) extraction using ketone compounds with physical properties superior to current commercial extractants

Dibutyl carbitol (DBC) and methyl isobutyl ketone (MIBK) are commercially available for the extraction of Au(III) from acidic chloride media through ion solvation. These extractants show high Au(III) extractability, but their physical properties have drawbacks in extraction processes. In this study, Au(III) extraction using a series of aliphatic ketone compounds was studied to find a novel extractant with advantageous properties compared with conventional extractants. These ketone compounds showed desirable Au(III) extractability, with those bearing shorter aliphatic chains showing higher extractability. Furthermore, their Au(III) extraction capacities exceeded industrial requirements. These compounds also had improved properties for metal processing compared with commercial extractants, namely, lower solubility in water, lower viscosity, and high flash points. A representative extractant, 2-nonanone, selectively extracted Au(III) over various metal ions. Gold extracted with 2-nonanone was recovered quantitatively as metallic gold by reduction using oxalic acid.     

有机化学碳链增长反应的探讨

通过对末端烯烃、末端炔烃、芳香烃、醛酮碳链增长反应的机理进行了简单的探讨,重在提高学生对基础知识的理解和应用,并逐步掌握化学反应的特点和规律,对有机化学反应进行分析,并正确判断有机化学反应的主要产物.