Mechanistic study of electrochemical oxidation of catechols in the presence of 4-hydroxy-1-methyl-2(1H)-quinolone: Application to the electrochemical synthesis

Electrochemical oxidation of catechols (1a-1c) has been studied in the presence of 4-hydroxy-1-methyl-2(1H)-quinolone (3) as a nucleophile in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a-1c) participate in Michael addition reactions with 3 to form the corresponding benzofuran (or isochromeno[4,3-c]quinoline) derivatives (6a-6c). The electrochemical synthesis of (6a-6c) has been successfully performed in an undivided cell in good yield and purity. The oxidation mechanism was deduced from voltammetric data and by coulometry at controlled-potential. The products have been characterized after purification by IR, ¹H NMR, ¹³C NMR and MS.     

4-氯-1-甲基-3-硝基-2(1H)-喹啉酮的合成

以N-甲基苯胺为起始原料,经过环合反应制得4-羟基-1-甲基-2(1H)-喹啉酮,再经硝化和氯代反应合成了目标化合物,该方法所用原料廉价易得,产物处理简单,适合工业化生产,总收率可达51.9%。     

Mechanistic study of electrochemical oxidation of 4-tert-butylcatechol: A facile electrochemical method for the synthesis of new trimer of 4-tert-butylcatechol

The electrochemical trimerization of 4-tert-butylcatechol via anodic oxidation of 4-tert-butylcatechol (1) is described. The mechanism of trimerization has been studied in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The electrochemical synthesis of trimer 3a has been successfully performed in an undivided cell in good yield and purity.     

Redox polymer-based reagentless horseradish peroxidase biosensors: Influence of the molecular structure of the polymer

Reagentless amperometric biosensors were prepared using a variety of nitrogen donor groups containing co-polymers. The polymers were coordinated with Os-bis-N,N-(2,2′-bipyridil)-dichloride via a ligand exchange reaction thus assuring an efficient electron-transfer pathway between the polymer-entrapped horseradish peroxidase and the electrode surface by means of a sequence of electron-hopping steps. The impact of structural features of the polymer such as spacer length between the Os-complex and the polymer backbone or the ratio of 4-vinylpyridine and butylmethacrylate in a co-polymer on the activity of the horseradish peroxidase biosensors was investigated.     

4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-1,2,4-三唑-5(1H)酮的两种合成方法

介绍了4,5 二氢 3 甲基 1 (4 氯 2 氟苯基) 1,2,4 三唑 5(1H)酮的两种合成方法。以 2 氟 4 氯苯肼作为原料,1 (乙氧基)乙叉基氨基甲酸乙酯法收率82 6%,“一锅法”收率 81%,化合物经核磁证实了结构,并对两种方法做了比较。该化合物是合成超高效除草剂唑酮草酯的重要中间体。     

左西孟旦中间体6-(4-氨基苯基)-5-甲基-4,5-二氢-3(2H)-哒嗪酮的合成工艺改进

以衣康酸为原料,与甲醇酯化反应生成β-衣康酸单甲酯,再经催化氢化生成3-甲基琥珀酸单甲酯,然后与氯化亚砜反应生成酰氯再与乙酰苯胺反应生成3-对乙酰氨基苯甲酰基丁酸甲酯,生成物经过水解,环合,生成目标化合物。产品结构经1H NMR确认,反应总收率65.7%。该合成工艺简便﹑合理﹑可行﹑适合工业化生产。     

4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-4-二氟甲基-1,2,4-三唑-5(1H)酮的合成方法

4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-4-二氟甲基-1,2,4-三唑-5(1H)酮是超高效含氟除草剂唑酮草酯的重要中间体,采用高温氟化的方法,通过优化反应条件,使目标化合物的合成收率达75.4%,含量达97.3%,降低了成本,更利于工业化生产.     

聚二(2-甲基-4-羟基-5-叔丁基苯)硫醚的合成

介绍了四步法合成聚二(2 甲基 4 羟基 5 叔丁基苯)硫醚:①以异丁烯和间甲酚为原料,以浓硫酸为催化剂合成3 甲基 6 叔丁基苯酚,并将剩余釜底液继续与间甲酚反应使3 甲基 6 叔丁基苯酚的收率接近100%;②硫磺与氯气反应合成二氯化硫,收率80%以上;③3 甲基 6 叔丁基苯酚与二氯化硫发生缩合反应生成二(2 甲基 4 羟基 5 叔丁基苯)硫醚,采用加入辅助溶剂法收率达到92%;④二(2 甲基 4 羟基 5 叔丁基苯)硫醚同氧气发生氧化偶联反应合成聚二(2 甲基 4 羟基 5 叔丁基苯)硫醚。氧化偶联反应的最佳条件:n〔二(2 甲基 4 羟基 5 叔丁基苯)硫醚〕/n(氧气)=2 5～3 0,n(氯化亚铜)∶n〔二(2 甲基 4 羟基 5 叔丁基苯)硫醚〕=1∶140,n(氯化亚铜)∶n(四甲基乙二胺)=1∶1 3的铜 胺络合物为催化剂,温度50℃,压力0 2MPa,反应时间2～3h,然后减压蒸出溶剂,最后得到淡黄色的聚二(2 甲基 4 羟基 5 叔丁基苯)硫醚,收率>99%。     

6,7-二氢-6-甲基-3-甲硫基吡喃[4,3-c]吡唑-4-(2H)-酮衍生物的合成及生物活性

6-甲基-5,6-二氢吡喃-2,4-二酮和二硫化碳、碘甲烷缩合得到5,6-二氢吡喃-2,4-二酮的二硫缩醛化合物,然后和取代肼反应得到1位取代和2位取代6,7-二氢-6-甲基-3-甲硫基吡喃[4,3-c]吡唑-4-(2H)-酮衍生物。其化学结构通过单晶X衍射、1HNMR、13CNMR、元素分析证实。生物活性测试结果初步表明,该类化合物表现出一定的杀菌和对前列腺癌细胞PC3的抑制活性。     

1-(2-氯苯基)-5(4H)-四唑啉酮的合成研究

1 (2 氯苯基 ) 5 (4H) 四唑啉酮 (Ⅰ)可由 2 氯硝基苯经三步合成反应制得。首先 ,2 氯硝基苯经铁粉还原得 2 氯苯胺 (Ⅱ) ,Ⅱ与碳酸二 (三氯甲基 )酯反应得 2 氯苯基异氰酸酯 (Ⅲ ) ,Ⅲ在DMF溶剂中 ,无水三氯化铝催化下与叠氮钠缩合得Ⅰ。三步收率分别为 90 %、80 %、90 % ,总收率为 6 5 %(以邻氯硝基苯计 ) ,产品质量分数达 95 %。     

相转移催化合成4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-1,2,4-三唑-5(1H)酮的工艺

[方法]4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-1,2,4-三唑-5(1H)酮是唑酮草酯的重要中间体。以4-氯-2-氟苯肼为原料,乙酸乙酯为反应溶剂,PEG-1000为相转移催化剂,经过脱水缩合、1,3-偶极加成、氧化脱氢等3步反应,合成4,5-二氢-3-甲基-1-(4-氯-2-氟苯基)-1,2,4-三唑-5(1H)酮。[结果]研究了催化剂种类与用量、溶剂、反应温度、物料配比对反应收率的影响,得到优化后的反应条件:n(乙醛)∶n(氰酸钠)∶n(乙酸)∶n(次氯酸钠)∶n(聚乙二醇-1000)∶(4-氯-2-氟苯肼)为1.80∶1.60∶1.84∶1.60∶0.04∶1.0,反应温度20~25℃。[结论]该工艺原料易得、反应条件温和、操作简单、收率较好,具有良好的工业应用价值。     

Application of the electrochemical quartz crystal microbalance technique to copper sonoelectrochemistry: Part 1. Sulfate-based electrolytes

The applicability of the electrochemical quartz crystal microbalance technique in an ultrasonic field created by an ultrasound probe is demonstrated for the electrodeposition of copper. Cyclic voltammetry and potentiostatic depositions in acidic sulfate-based copper electrolytes were performed at different ultrasonic intensities. The electrochemical quartz crystal microbalance was operated in ultrasonic fields with intensities up to 30 W cm⁻². For cyclic voltammetry, potential resolved and averaged (apparent) current efficiencies were calculated from mass and charge data in function of the amplitude of the ultrasonic horn. Ultrasound slightly affected the current efficiencies during copper deposition in cyclic voltammetry, but did not change the efficiencies during dissolution. During potentiostatic depositions the current efficiency increased from 84% to almost 100% upon application of ultrasound. Morphology of deposits prepared by potentiostatic depositions was analyzed by scanning electron microscopy, and found to be different at high ultrasonic intensities.     

强酸性离子交换膜催化合成二氢嘧啶酮药物中间体

在HF 101强酸性离子交换膜的存在下,由对羟基苯甲醛、乙酰乙酸甲酯与脲一步合成了5 甲氧羰基 4 (4 甲氧苯基) 6 甲基 3,4 二氢嘧啶 2(1H) 酮。当对羟基苯甲醛、乙酰乙酸甲酯与脲的摩尔比为1∶2∶5,乙醇作溶剂,3g离子交换膜,回流2h,产物收率达95.4%。同时研究了离子交换膜作为催化剂的重复使用情况。     

3-氨基-7,8-二甲氧基-2(1H)-喹诺酮的合成

为了改进和优化3-氨基-2(1H)-喹诺酮环的合成工艺,从芳草醛出发,依次经过乙酰化、硝化、甲基化、还原,制备出2-氨基-3,4-二甲氧基苯甲醛(Ⅴ),Ⅴ与硝基乙酸甲酯环合得3-硝基-7,8-二甲氧基-2(1H)喹诺酮(Ⅵ),还原Ⅵ,得到3-氨基-7,8-二甲氧基-2(1H)-喹诺酮。优化后的环合条件为:以体积比7∶3的甲苯和环己烷为混合溶剂,哌啶为催化剂;Ⅵ最佳还原条件为:乙醇为溶剂,5%钯碳和甲酸铵为还原剂。在该条件下,3-氨基-7,8-二甲氧基-2(1H)-喹诺酮合成总收率从邻氨基苯甲醛(Ⅴ)计可达70%以上。     

Preparation and electrochemical characterization of palladium single crystal electrodes in 0.1 M H2SO4 and HClO4: Part I. Low-index phases

The electrochemical properties of Pd(1 1 1), Pd(1 0 0) and Pd(1 1 0) single crystal bead electrodes, prepared by a novel electron beam heating and inductive annealing technique, have been characterized in 0.1 M sulfuric acid and 0.1 M perchloric acid by cyclic voltammetry and chronoamperometry. Hydrogen and (hydrogen) sulfate adsorption as well as surface oxidation were found to depend strongly on the crystallographic orientation and the nature of the electrolyte. The combination of charge displacement and voltammetric experiments allowed the determination of the potentials of zero total charge (E_pztc) of Pd(1 1 1) and Pd(1 0 0). The values of E_pztc in sulfuric acid were found to be more negative than in perchloric acid. The estimation of E_pztc for Pd(1 1 0) was hampered by the superposition with hydrogen absorption. The electro-oxidation of irreversible adsorbed carbon monoxide monolayers was studied on the three low-index Pd electrodes. The onset potential of the CO oxidation reaction follows the sequence Pd(1 0 0) < Pd(1 1 0) < Pd(1 1 1). Chronoamperometric experiments revealed a pronounced structure sensitivity of the reaction kinetics. The processes involved are determined by nucleation of oxygen-containing species on defect (step) sites and by slow diffusion of CO_ads on (1 1 1) terrace sites.     

Adsorption of mercaptopropionic acid onto Au(1 1 1): Part II. Effect on copper electrodeposition

Copper deposition in the presence of an organic additive (3-mercaptopropionic acid, MPA) was studied by cyclic voltammetry and in situ scanning tunneling microscopy (STM) and the results are compared to those for additive-free solutions. It is shown that underpotential deposition (upd) of copper onto a fully MPA-covered electrode produces a defect-rich substrate, but the defects are blocked by the dense organic film for bulk deposition, resulting in a low number of nuclei. A grain-refining effect of MPA, however, was found, when Cu deposition was initiated shortly after addition of MPA to the solution, i.e., for a low-coverage MPA adlayer.     

1-氯-2-甲基-4-乙酰氧基-2-丁烯制备方法的改进

用次氯酸钙和乙酸作用生成的缓冲体系非常温和,在此体系下以异戊二烯为原料进行的氯醇化反应收率可达88.6%,反应混合物可以进一步酯化重排制备维生素A的中间体1-氯-2-甲基-4-乙酰氧基-2-丁烯。     

微波辐射下合成4-(4-氯苯基)-6-甲基-5-乙氧羰基-3,4-二氢嘧啶-2(1H)-酮

研究了微波辐射催化合成标题化合物的方法。最优合成条件:催化剂氨基磺酸0.8g,微波功率240W,辐射时间4min,n4-氯苯甲醛∶n乙酰乙酸乙酯∶n尿素为1.0∶1.2∶1.5,在此条件下产率达94.2%。     

HClO4催化合成3,4-二氢嘧啶-2-酮

HClO4催化下,芳香醛、β-酮酸酯、脲或硫脲(物质的量比1∶1∶1.5)在冰醋酸中环化缩合,合成3,4-二氢嘧啶-2-酮衍生物,反应时间3.5 h,产率75%~98%。     

强酸性离子交换膜催化合成5-乙氧羰基-4-(4-甲氧苯基)-6-甲基-3,4-二氢嘧啶-2(1H)-酮

在HF-101强酸性离子交换膜的存在下,由茴香醛、乙酰乙酸乙酯与脲一步合成了5 乙氧羰基 4 (4 甲氧苯基) 6 甲基 3,4 二氢嘧啶 2(1H) 酮。当茴香醛、乙酰乙酸乙酯与脲的摩尔比为1:2:5,乙醇作溶剂,4g离子交换膜,回流2h,产物收率达95 2%。同时研究了离子交换膜作为催化剂的重复使用情况。