Electrochemical synthesis of new catechol derivatives

Electrochemical oxidation of catechols (1a-e) has been studied in the presence of 2-acetylcyclopentanone (3) as a nucleophile in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a-e), participate in Michael addition reactions with anion of 2-acetylcyclopentanone (3) and via EC mechanism pathway, converted to corresponding catechol derivatives (4a-e). In this work, we derived novel catechol derivatives with good yields based on electrochemical oxidation in aqueous solutions, at carbon electrode in an undivided cell, using environmentally friendly method.     

一种合成原二氯乙酸三乙酯的新方法

报道了以三氟三氯乙烷和乙醇钠乙醇溶液为原料,在高压釜中合成标题化合物的新方法。通过单因素实验确定了该方法的较优合成条件为:三氟三氯乙烷和乙醇钠的物质的量比为1∶5.5,反应温度为140℃,反应时间为9 h,此时目标产物的收率可达77.7%。该合成方法操作简单,反应条件较为温和。     

一种合成水解聚马来酸的新方法

以３０％的过氧化氢为引发剂,以混合过渡金属离子（Ｍ＾２＋）为主催化剂,合成了分子量在６５０～８５０之间的水解聚马来酸,并进行了工业扩大生产,取得了预期的效果,工业生产的水解聚马来酸达到或超过了一等吕的国家标准。该方法所用的催化剂和引发剂易得,用量少,价格低。工业扩大生产出的产品平均相对分子量分布范围窄。具有较好的阻垢作用。     

Synthesis and characterization of dehydroabietic acid derivatives suitable for surfactant synthesis

The syntheses of derivatives of dehydroabietic acid suitable for further manipulation into surfactants are presented. The compounds are produced at very high yields and purity. They contain several different functional groups, e.g., carboxylic acid, amine, ester, alcohol, and an aromatic group. The functional groups are useful as the linking unit to the hydrophilic part in synthesizing surfactants.     

Electrochemical study of catechols in the presence of 2-thiazoline-2-thiol: application to electrochemical synthesis of new 4,5-dihydro-1,3-thiazol-2-ylsulfanyl-1,2-benzenediol derivatives

Electrochemical oxidation of catechols (1a–d) has been studied in the presence of 2-thiazoline-2-thiol (3) as a nucleophile in aqueous solution, using cyclic voltammetry and controlled potential coulometry. The results indicate that the quinones derived from catechols (1a–d), participate in Michael addition reactions with 2-thiazoline-2-thiol and via an EC mechanism pathway, convert to the corresponding catechols derivatives (4a–d and 4′d). The electrochemical synthesis of compounds (4a–d and 4′d) has been successfully performed at a carbon rod electrode and in an undivided cell with good yield and high purity. The products have been characterized by IR, ¹H NMR, ¹³C NMR and MS.     

一种合成α-鼠胆酸的新方法

以猪去氧胆酸为原料,经酯化、C-6位选择性氧化、C-7位羟基化、C-6位羰基还原和水解等步骤合成α-鼠胆酸,其结构经~1HNMR、~(13)CNMR、HRMS确认,反应总收率达到28.9%±0.3%。考察了催化剂对中间体Ⅱ收率的影响和工艺的稳定性;探索了不同氧化剂对中间体Ⅱ中C-3和C-6位羟基氧化的选择性及收率的影响,筛选到可高效选择性氧化C-6位羟基的氧化剂2-碘酰基苯甲酸(IBX),同时考察了IBX与中间体Ⅱ的物料比对中间体Ⅲ收率的影响及工艺的稳定性。结果表明:浓盐酸作为催化剂,中间体Ⅱ的收率约99%;IBX可以选择性氧化中间体Ⅱ中C-6位羟基,且当n(中间体Ⅱ)∶n(IBX)=1∶1.20时,中间体Ⅲ的收率达到82.3%;获得了中间体Ⅲ的X射线单晶结构,确定了其绝对构型。     

A new strategy for the synthesis of dinucleotides loaded with glycosylated amino acids--investigations on in vitro non-natural amino acid mutagenesis for glycoprotein synthesis

The in vitro non-natural amino acid mutagenesis method provides the opportunity to introduce non-natural amino acids site-specifically into proteins. To this end, a chemically synthesised aminoacylated dinucleotide is enzymatically ligated to a truncated suppressor transfer RNA. The loaded suppressor tRNA is then used in translation reactions to read an internal stop codon. Here we report an advanced and general strategy for the synthesis of the aminoacyl dinucleotide. The protecting group pattern developed for the dinucleotide facilitates highly efficient aminoacylation, followed by one-step global deprotection. The strategy was applied to the synthesis of dinucleotides loaded with 2-acetamido-2-deoxy-glycosylated amino acids, including N- and O-beta-glycosides and O- and C-alpha-glycosides of amino acids, thus enabling the extension of in vitro non-natural amino acid mutagenesis towards the synthesis of natural glycoproteins of high biological interest. We demonstrate the incorporation of the glycosylamino acids--although with low suppression efficiency--into the human interleukin granulocyte-colony stimulating factor (hG-CSF), as verified by the ELISA technique.     

Paired electrochemical synthesis of new organosulfone derivatives

Electrochemical oxidation of “cathodically generated 4-aminocatechol (2)” has been studied in the presence of 4-toluenesulfinic acid (4a) and benzenesulfinic acid (4b) as nucleophiles in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the o-benzoquinone derived from 4-aminocatechol (2) participates in Michael addition reaction with 4a or 4b to form the corresponding new organosulfone derivatives (5a and 5b). In this work we have proposed a mechanism for the electrode process. A Fe(CN)₆³⁻/Fe(CN)₆⁴⁻ redox mediator was used for the anodic oxidation of 4-aminocatechol (2) to the corresponding o-quinone 3. The indirect electrochemical process consists of a multi-step such as (a) cathodic reduction of 4-nitrocatechol (1) to 4-aminocatechol (2), (b) chemical oxidation of 4-aminocatechol (2) to 4-aminoquinone (3) with the resulting Fe(CN)₆³⁻, (c) the chemical reaction of 4-aminoquinone (3) with 4-toluenesulfinic acid (4a) or benzenesulfinic acid (4b), and (d) the anodic regeneration of Fe(CN)₆³⁻. The paired electrochemical synthesis of organosulfone derivatives (5a and 5b) has been successfully performed in an one-pot process at carbon rod electrode as a working and platinum as a counter electrode in an undivided cell.     

A novel solid acid for synthesis of bisphenol A

A novel solid acid was prepared from boric, phosphorous and sulfuric acid by a simple method, and characterized by FT-IR, XRD and TG. Surprisingly, the prepared solid acid is an effective catalyst for the synthesis of bisphenol A from condensation of phenol with acetone. The high conversion of acetone (91.8%) and selectivity of bisphenol A (93.4%) were achieved in the presence of the novel catalyst.     

乙二胺-乙酸合成方法的改进

通过增大乙二胺的加入量，改变原料的加入顺序和采用浓盐酸提取的方法，对乙二胺-乙酸的合成做了改进。该方法简化了合成步骤，并使产率达到了80％以上。     

催化剂对4-乙酰氧基苯甲酸的合成影响研究

以对羟基苯甲酸(PHB)和乙酸酐(Ac2O)为原料,醋酸(HAc)为溶剂,考察浓硫酸和杂环化合物催化合成4-乙酰氧基苯甲酸(PABA),反应物配比为羟基苯甲酸∶乙酸酐∶醋酸=1∶1.05∶0.5,确定最佳催化剂加入量、反应时间和反应温度。结果表明,浓硫酸为催化剂时,最佳反应时间2 h,反应温度100℃,催化剂加入量为PHB质量的4%,产率67%;杂环化合物P为催化剂时,最佳反应温度80℃,反应时间2 h,催化剂加入量为PHB质量的0.3%,产率99.8%。杂环化合物比浓硫酸对PABA合成有更好的催化活性,反应条件温和,具有较好的工业化应用前景。     

(S)-对羟基苯基乳酸衍生物的合成进展

光学纯的(S)-对羟基苯基乳酸衍生物是合成新型抗糖尿病药物和混杂多肽的有价值的关键中间体。综述了合成(S)-对羟基苯基乳酸衍生物的各种方法,并分析了各种合成方法的优缺点。     

2-硝基苯胺-4-磺酸的合成研究

以溶剂汽油和石油醚按一定比例复配成混合型溶剂,用该溶剂合成了2-硝基苯胺-4-磺酸。产品收率在的91％以上,溶剂回收率在95％以上。     

邻乙氧基苯甲酸合成方法的改进

采用两种新方法合成了邻乙氧基苯甲酸：以水杨酸甲酯和溴乙烷为原料在碘化钾催化下先制得邻乙氧基苯甲酸甲酯，再经水解、酸化得邻乙氧基苯甲酸；由水杨酸和硫酸二乙酯经碱性下取代、酸化制得了邻乙氧基苯甲酸。两种方法的收率分别为89．2％和92．2％。     

酸性蓝2BNL染料的合成

用2-氨基苯酚-4-磺酸重氮化,与邻羧基二苯腙进行偶合,然后铜化得到新的蓝染料。该染料的各项应用性能达到或超过酸性蓝168,特别是溶解度提高5倍。本文介绍了新染料的化学结构及合成方法。     

Studies on the enzymatic synthesis of lipophilic derivatives of natural antioxidants

The esterification of some natural antioxidants such as cinnamic acid derivatives and ascorbic acid in non-aqueous media, catalyzed by immobilized lipases from Candida antarctica and Rhizomucor miehei, was investigated. The alcohol chain length affected the rate of esterification of cinnamic acids by both lipases. Higher reaction rates were observed when the esterification was carried out with medium- or long-chain alcohols. The rate also depended on aromatic acid structure. The reactivity of the carboxylic function of the cinnamic acids was affected by electron-donating substituents in the aromatic ring. Higher yields were observed for the esterification of p-hydroxyphenylacetic acid (97%) catalyzed by C. antarctica lipase and for the esterification of cinnamic acid (59%) catalyzed by R. miehei lipase. Candida antarctica lipase was more suitable for producing ascorbic acid fatty esters, catalyzing with a relatively high yield (up to 65% within 24 h) the regioselective esterification of ascorbic acid with various fatty acids in 2-methyl-2-propanol. The reaction rate and yield depended on the fatty acid chain length and on the molar ratio of reactants. All ascorbic acid fatty esters produced by this procedure exhibited a significant antioxidant activity in a micellar substrate composed of linoleic acid.     

电解合成丁二酸的研究进展

综述了国内外电解合成丁二酸的方法,详细介绍了电解反应过程中阴极材料、阳极材料、电解槽结构和隔膜材料的发展趋势.分析结果表明铅及铅合金阴极凭借其自身的优势,仍然是工业生产所采用的最主要的阴极材料;最适合的阳极材料是钛基氧化钌、铱或钽铱钛合金;而且无需使用任何形式的隔膜;未来最具有应用前景的研究方向是Ti或Ti/TiO2阴极.     

The synthesis of silicon oleochemicals by hydrosilylation of unsaturated fatty acid derivatives

The hydrosilylation of fatty acid esters with terminal or internal double bonds catalysed by H₂ PtCl₆ is described. The reaction was carried out with good yields at ambient pressure under mild conditions. Methyl undec‐10‐enoate was reacted with chloro‐ or alkoxyhydrosilanes giving moderate to good yields (41—77%) and even its reaction with alkylhydrosilanes produced low yields (below 20%). Under optimised conditions the hydrosilylation of methyl linoleate gave only with reactive chlorohydrosilanes acceptable yields, between 25 to 83%, of regioisomers. The hydrosilylation of methyl α‐linolenate with dimethylchlorosilane gave a mixture of regioisomeric 1:1‐ and 2:1‐hydrosilylation adducts in a total yield of 40%. The hydrosilylation of ethyl oleate did not proceed at all under our conditions. In the case of methyl undec‐10‐enoate a biphasic solvent system permitted the simple separation and reuse of the homogeneous catalyst.     

气相色谱法分析合成苯乙酸用CO气体

介绍有关气相色谱法对合成苯乙酸用CO气体的分析测试,探讨了减小该测定误差的方法。     

邻氯苯甲酸的合成研究进展

本文总结了国内外近年来邻氯苯甲酸合成的研究进展,主要介绍了重氮化法、氧化法、氯化水解法、仿生催化氧化法,分析了各工艺的优缺点,并结合目前国内的发展状况,对今后我国邻氯苯甲酸的研制和发展作出展望。