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1.
报道了一种分离甲苯、2-甲基噻吩和3-甲基噻吩的方法。通过氯化反应将沸点非常接近的甲苯、2-甲基噻吩和3-甲基噻吩转化为沸点相差较大的甲苯(111℃)、2-氯-5-甲基噻吩(155℃)和2,5-二氯-3-甲基噻吩(185℃),通过对比实验获得氯代反应的最佳条件为:2-甲基噻吩和3-甲基噻吩与磺酰氯的投料比1∶1. 75,反应温度65℃,反应时间2 h。通过精馏将三者分离并提纯,得到甲苯、高附加值的2-氯-5-甲基噻吩和2,5-二氯-3-甲基噻吩产品;通过催化还原反应将2-氯-5-甲基噻吩和2,5-二氯-3-甲基噻吩分别还原为2-甲基噻吩和3-甲基噻吩,达到完全分离、提纯的目的。 相似文献
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构建了羰基还原酶CR2重组酶体系,并优化了相关的酶促催化反应条件.通过在催化体系中添加辅酶NADP+(0.1 mmol/L)和辅底物葡萄糖(120 g/L),在30℃及p H=8.0的条件下反应4 h,CR2重组酶体系不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP,10 g/L),合成了高光学纯度(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺[(S)-DHTP,e.e.值99.9%],产率为62%.在酶促催化过程中,由于辅酶循环生成葡萄糖酸导致反应体系p H值下降而影响催化效率.通过调控反应体系p H值,(S)-DHTP的产率提高到68%.不同浓度底物的反应过程表明底物对CR2酶促反应具有抑制作用,且在10 g/L底物浓度下反应的时空产率可达1.3 g·L-1·h-1. 相似文献
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Staudinger 反应是合成β-内酰胺类化合物最重要的方法之一. 3-(噻吩-2-基)-β-内酰胺是一类重要的β-内酰胺类衍生物. 发展了一种从1-(噻吩-2-基)-4,4,4-三氟-1,3-丁二酮和对甲苯磺酰叠氮方便地制备1-(噻吩-2-基)-2-重氮基乙酮的新方法, 利用1-(噻吩-2-基)-2-重氮基乙酮加热分解生成的噻吩-2-基烯酮参与的Staudinger反应合成了一系列3-(噻 吩-2-基)-β-内酰胺衍生物, 并研究了噻吩-2-基烯酮参与的Staudinger反应的立体选择性. 实验结果表明噻吩-2-基烯酮是比苯基烯酮更富电子的Moore烯酮, 其电子性质介于对甲氧基苯基烯酮和对甲基苯基烯酮之间. 相似文献
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有机相酶催化氨解反应拆分制备(R)-4-氯-3-羟基丁酸乙酯 总被引:1,自引:0,他引:1
通过脂肪酶催化的氨解反应拆分4-氯-3-羟基丁酸乙酯. 经过对脂肪酶及反应溶剂的筛选, 确定最佳脂肪酶及溶剂分别为Novozym435和二氧六环; 并在该反应体系中考察了温度、底物浓度、酶浓度与摇床转速对反应的影响. 综合考虑反应的反应速度和对映体选择率, 确定较佳的反应条件为: 温度30 ℃、底物浓度0.5 mol/L、酶量10 mg/mL、摇床转速200 n/min. 反应35 h后, ee可以达到99%以上, 此时转化率为57.7%. 相似文献
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考察了利用安大略假丝酵母(Candida ontarioensis)静息细胞不对称催化2-氯-1-(3-氯苯基)乙酮合成(R)-2-氯-1-(3-氯苯基)乙醇的转化反应条件.结果表明,当底物浓度为10g/L时,在最适转化条件下反应72h,产物的ee值和产率分别达到99.9%和99.0%.采用4g/L十六烷基三甲基溴化铵对Candida ontarioensis细胞于4℃通透性处理20min后,全细胞的酶活提高2倍以上.当底物浓度提高为30g/L,转化24h后,产物的ee和产率分别达到99.9%和97.5%.该研究为高效制备(R)-2-氯-1-(3-氯苯基)乙醇提供了可行途径,并为生物催化合成芳基手性醇类手性中间体提供了理论指导。 相似文献
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将新型氯化钴/吡嗪-2-羧酸钾催化体系用于苄基氯双羰化反应,并对反应条件进行了优化. 结果表明,最佳反应条件为: 氯化钴浓度0.03 mol/L,吡嗪-2-羧酸(Pzca)浓度0.156 mol/L,n(Pzca)/n(KOH)=1,n(Ca(OH)2)/n(苄基氯)=2.7,V(1,4-二氧六环)/V(H2O)=5,反应温度70 ℃,CO压力2.0 MPa,反应时间10 h,此时β-苄基-α-苯丙酮酸的产率为77.3%,双羰化选择性为99.6%. 该催化体系能有效地抑制单羰化反应,双羰化反应的选择性和苄基氯转化率都较高. 同时对该体系的催化活性体进行了初步解释,并用红外光谱和质谱对产物结构进行了表征. 相似文献
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聚[2-(2-氯乙氧基)乙氧基)_x(三氟乙氧基)_(2-x)]磷腈合成和气体分离性能研究 总被引:1,自引:1,他引:0
六氯环三聚磷腈经二次重结晶一次减压升华纯化后,通过真空热开环聚合和亲核取代反应,用不同摩尔比的2-(2-氯乙氧基)乙醇钠和三氟乙醇纳(1∶3;1∶5;1∶6.5)作为亲核取代试剂混取代聚二氯磷腈,再经多次非溶剂沉淀纯化得到目标聚合物聚[(2-(2-氯乙氧基)乙氧基)x(三氟乙氧基)2-x]磷腈.利用31P-NMR监测,以确保得到纯化的聚合物.采用1H-NMR、FT-IR、GPC、DSC、XRD等测试手段对所得到的聚合物进行了结构表征和性能测试,并利用自制的压力法透气性能测定仪测定了这些聚合物的气体渗透系数.结果表明,三氟乙氧基和2-(2-氯乙氧基)乙氧基两种基团已接枝在聚磷腈侧链上,分别得到x值为0.19,0.18和0.08的3种聚[(2-(2-氯乙氧基)乙氧基)x(三氟乙氧基)2-x]磷腈,其玻璃化温度分别为-6.37℃,-12.85℃和-25.68℃,重均分子量为5.4×105,6.8×105和1.5×105,在同样的反应条件下,三氟乙氧基较2-(2-氯乙氧基)乙氧基有更强的竞争取代率.这种混取代聚磷腈较单一取代基的聚三氟乙氧基磷腈结晶度小,在本实验中两种取代基比例适中的聚[(2-(2-氯乙氧基)乙氧基)0.18(三氟乙氧基)1.82]磷腈的结晶度降至10.1%,这种聚合物显示出较高的气体渗透系数,CO2和He的气体渗透系数达到88.9和60.6 barrer,CO2/CH4和He/CH4的选择系数达到24.1和16.4,在天然气行业显露出良好的应用潜力.此外这类聚合物表现出特殊的H2/N2选择性,选择系数在0.2左右,N2的渗透系数为8.5 barrer,因而在合成氨行业显示出特殊的应用潜力. 相似文献
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L. K. Papernaya E. N. Deryagina A. I. Albanov 《Chemistry of Heterocyclic Compounds》2002,38(9):1052-1054
At the alkylation of monoethanolamine vinyl ether with 2-chloro-5-(chloromethyl)thiophene in ethyl alcohol (60-70°C) a product of disubstitution and transvinylation, viz. N,N-bis(5-chloro-2-thienylmethyl)-N-(2-hydroxyethyl)ammonium chloride is formed. The analogous reaction in the absence of solvent proceeds with the formation of N-(5-chloro-2-thienylmethyl)-N-(2-vinyloxyethyl)amine. 相似文献
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Kinetic Resolution of 2-Chloro-1-(3,4-dichlorophenyl)ethanol by Lipase-Catalyzed Transesterification
Kinetic resolution of racemic 2-chloro-1-(3,4-dichlorophenyl)ethanol was performed by free Alcaligene sp. lipase-catalyzed irreversible transesterification affording the (R)-isomer with ≥95% ee and the (S)-isomer with ≥90% ee. The activity of lipase Alcaligene sp. strongly depends on the basicity of the reaction system, and an organic base such as triethylamine can enhance the activity of the lipase and enantioselectivity markedly. 相似文献
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Shuyin Liu Guihua Xiong Fengxi Li Shushu Wei Zhi Wang 《Green Chemistry Letters and Reviews》2016,9(4):190-195
(S)-3-hydroxy-3-(2-thienyl) propanenitrile, which is the key chiral building block for the synthesis of (S)-duloxetine, was successfully prepared via enantioselective transesterification catalyzed by lipase under ultrasound irradiation. Compared with conventional shaking, the enzyme activity and enantioselectivity were dramatically enhanced under ultrasound irradiation. Under optimum reaction conditions (solvent: n-hexane, ultrasound power: 150?W, aw: 0.33, temperature: 40°C), Pseudomonas sp. lipase exhibited an excellent catalytic performance (enzyme activity: 81.5?μmol?g?1?min?1, E-value: 65.4). The reaction achieved its equilibrium in approximately 7?h with a conversion of 53.9% and high enantiopurity (99% ee) of (S)-3-hydroxy-3-(2-thienyl) propanenitrile could be obtained. 相似文献
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为了寻找高效低毒的非甾体抗炎药物, 将5-氯-2-吲哚酮与氯甲酸苯酯经酯化及水解制得1-苯氧羰基-5-氯-2-吲哚酮, 在4-N,N-二甲氨基吡啶作用下与对甲磺酰基苯甲酰氯反应, 经酸化得1-苯氧羰基-3-[羟基-(p-甲磺酰基)苯甲撑基]-5-氯-2-吲哚酮(II1), 最后与相应的胺(氨)反应, 经盐酸中和制得未见文献报道的目标化合物II2~II15, 其结构经IR, 1H NMR, MS和元素分析确证. 二甲苯致小鼠耳肿胀模型测试显示II10, II11, II15具有明显的抗炎活性; 角叉菜胶致大鼠足跖肿胀模型试验结果表明, II10, II11抗炎活性与双氯芬酸钠和替尼达普钠相当(P>0.05); 其中II11的胃肠道副作用显著小于双氯芬酸钠(P<0.05)和替尼达普钠(P<0.01). 相似文献
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M.J. Al-Darwich A. Plenevaux C. Lemaire G.D. Fiore L. Christiaens D. Comar A. Luxen 《Journal of fluorine chemistry》1996,80(2):117-124
(S)-4-Chloro-2-fluorophenylalanine and (S)-(α-methy)-4-chloro-2-fluorophenylalanine were synthesized and labeled with no carrier added (n.c.a.) fluorine-18 through a radiochemical synthesis relying on the highly enantioselective reaction between 4-chloro-2-[18F]fluorobenzyl iodide and the lithium enolate of (2S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3-methyl-1,3-imidazolidine-4-one for (S)-4-chloro-2-[18F]fluorophenylalanine and (2S,5S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3,5-dimethyl-1,3-imidazolidine-4-one for (S)-(α-methyl) -4-chloro-2-[18F] fluorophenylalanine. Quantities of about 20–25 mCi were obtained at the end of sy nthesi s, ready for injection after hydrolysis and high performance liquid chromatography (HPLC) purification, with a radiochemical yield of 17%–20% corrected to the end of bombardment after a total synthesis time of 90–105 min from [18F] fluoride. The enantiomeric excesses were shown to be 97% or more for both molecules without chiral separation and the radiochemical and chemical purities were 98% or better. 相似文献
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M. Judith Percino Víctor M. Chapela Omar Urzúa Ling-Fa Montiel Cecilia Rodríguez-Barbarín 《Research on Chemical Intermediates》2007,33(7):623-629
The novel intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol or 2-[2′-(1-hydroxy-1-(p-fluorophenyl)ethyl]pyridine and the corresponding novel dehydration compound 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene or 2-[p-fluorophenylvinyl]pyridine were obtained from the condensation reaction of p-fluorophenylaldehyde and 2-picoline under catalyst-and solvent-free conditions. The intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol was obtained at 42 h reaction time and temperature of 120°C, respectively. 1H-NMR, IR spectroscopic data of the 1-(p-fluorophenyl)-2-(2-pyridyl)ethanol clearly showed the presence of the-CH2-CHOH-group. The compound was obtained as a white powder with m.p. 121–122°C and a yield of 8%. For 1-(p-fluorophenyl)-2-(2-pyridyl)ethene, the reaction conditions were similar, but the reaction temperature was increased to yield
the double bond in the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene. At the reaction temperature of 140°C, the compound was a slightly brown powder with a
m.p. of 78°C and yield of 18%. 1H-NMR, IR spectroscopic data for the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene showed the presence of a double bond in trans configuration (-CH=CH-), characteristic of a styrylpyridine. 相似文献
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In this paper, stereocontrolled tandem Michael addition-elimination reaction of the novel chiral source, 5-(l-menthyloxy)-3,4-dichloro-2(5H)-furanone, with various thiols and amines has been investigated. A series of new enantiomerically pure compounds, 5–(l-menthyloxy)-4-substituted-3-chloro-2(5H)-furanones, were obtained in good yields with d. e. ? 98% under mild conditions. 相似文献
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D. I. D'yachenko A. G. Mustafin V. V. Shereshovets N. N. Kabal'nova V. P. Kazakov I. B. Abdrakhmanov G. A. Tolstikov 《Russian Chemical Bulletin》1998,47(8):1611-1612
An unusual direction of the reaction of 2-(cyclopent-2-enyl)aniline hydrochloride with dimethyldioxirane was found: the formation
of two isomeric products,viz., 3- and 6-chloro-2-(cyclopent-2-enyl)anilines, was observed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1654–1655, August, 1998. 相似文献