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噻唑类化合物是一类含有硫和氮原子的五元杂环化合物,广泛地应用于农药、化工和医药等领域。L-噻唑烷-4-甲酸是合成噻苯咪唑的关键中间体,具有广阔的应用前景。本文采用正交设计法对L-噻唑烷-4-甲酸的合成工艺进行优化,首先根据单因素实验结果确定四个主要影响因素分别为:反应时间、甲醛用量、反应温度和溶剂用量,同时确定每个因素的四个水平。以L-噻唑烷-4-甲酸的收率为考察指标,根据L16(44)正交设计法进行16次实验。研究结果表明:反应时间4 h、甲醛用量1∶1. 2、反应温度40℃、溶剂用量1∶1. 5为L-噻唑烷-4-甲酸最佳合成工艺。通过结果分析得出,四个因素中反应时间是实验结果的最大影响因素,甲醇用量、反应温度和溶剂用量对实验结果也有显著影响。 相似文献
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微波快速合成L—噻唑烷—4—甲酸及其乙酯的研究 总被引:6,自引:0,他引:6
在微波常压反应条件下,用L-半胱氨酸合成L-噻唑烷-4-甲酸和L-噻唑烷-4-甲酸乙酯。讨论了微波功率和反应时间对产率的影响。 相似文献
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研究了用HPLC法监控L-噻唑烷-4-甲酸乙酯合成关键步骤酯化反应。色谱条件:YMC-Pack Pro C18反相柱(4.6 mm×150 mm×5μm);0.01 mol/L磷酸二氢钠溶液(用磷酸调节pH为2.0)-甲醇为流动相,检测波长210 nm;流速1.0 mL/min。酯化反应液在0.158~1.278 mg/mL范围内线性关系良好(相关系数r=0.997 6);加标平均回收率为94.70%,重复进样的RSD为0.08%~1.62%,该方法的准确度高,精密度好,实际监测效果好。 相似文献
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本文选用结晶三氯化铝作为酯化反应的催化剂合成甲酸丙酯和甲酸异丙酯,研究了该催化剂存在下影响两种酯合成的基本条件,从而确定了催化剂用量为2~3g,醇酸摩尔比为1.2,在最佳条件下两种酯产率均能达到85%以上,并克服了硫酸作催化剂所产生的弊端。 相似文献
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Rapid synthesis of 4-ethyloctanoic acid by means of microwave irradiation is described. Diethyl malonate reacted with 2-ethyl-1-bromohexane in the presence of sodium ethoxide to give diethyl (2-ethylhexyl)malonate (1b). 1b was saponified in the solution of ethanol and potassium hydroxide and then acidified to form (2-ethylhexyl)propanedioic acid (1c), and 1c was heated and decarboxylized to give 4-ethyloctanoic acid (1d). The influence of reaction temperature and reaction time on the yield of 1b and the effect of reaction time on the yield of 1c and 1d were investigated in order to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 1b were a mole ratio of sodium to diethyl malonate to 2-ethylhexyl bromide of 0.1:0.11:0.11, a reaction temperature of 80-85 °C, and a reaction time of 2-2.5 h. The yield of 1b was about 79%. 1b was saponified for 30 min and then acidified to form 1c, and the yield of 1c was 96%. 1c was heated for 16 min at 180°C to give 1d, and the yield of 1d was about 90%. The overall yield of 1d is 70% under microwave irradiation. The reaction time was reduced greatly. In order to compare the result of microwave irradiation with that of an oil bath, the reactions were also performed in an oil bath. The structures of intermediates, product and by-product were confirmed by HRMS, (1)H NMR, (13)C-NMR and IR. 相似文献
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5-(4-羟基苄叉)—噻唑烷-2,4-二酮是抗糖尿病药的关键中间体,本文以硫脲为原料,经闭环、中和、水解、缩合4步反应合成得到目标物,总收率40%。 相似文献
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以水杨醛、丙二酸二乙酯为原料,二乙胺为催化剂,采用微波辐射技术合成香豆素-3-羧酸乙酯,利用正交实验设计考察了微波功率、原料配比、催化剂用量、辐射时间、溶剂用量对产物产率的影响.结果表明,当摩尔比水杨醛:丙二酸二乙酯:二乙胺=1∶1.3∶0.3时,5 mL乙醇,采用600 W微波辐射4 min,香豆素-3-羧酸乙酯产率... 相似文献
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以硫酸氢钠为催化剂,采用微波辐射,由间苯二酚与乙酰乙酸乙酯缩合制备7-羟基-4-甲基香豆素。结果表明,微波辐射合成7-羟基-4-甲基香豆素的最佳反应条件为:n(间苯二酚)∶n(乙酰乙酸乙酯)=1.0∶1.0,硫酸氢钠0.4 g,10 mL环己烷,反应温度100℃,微波辐射时间12 min,微波功率500 W,产率91.0%。 相似文献
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