共查询到18条相似文献,搜索用时 140 毫秒
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5-羟甲基噻唑合成工艺的研究 总被引:4,自引:0,他引:4
以2-氯-5氯甲基噻唑为主要原料,经酯化、还原、水解三步反应后合成5-羟甲基噻唑。以醋酸和锌粉为还原材料,采用催化剂使还原反应在常压和较低温度下进行。三步反应总收率达到54%,产品纯度在98%以上。探讨了酯化时间、催化剂用量、水解温度和时间等因素对收率的影响。 相似文献
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2-氯-5-氯甲基噻唑的合成方法及其应用 总被引:5,自引:0,他引:5
2-氯-5-氯甲基噻唑是合成烟碱类农药的重要中间体。本文简述了2-氯-5-氯甲基噻唑的几种合成方法,以及以其为原料合成的几种新型农药的合成及应用。 相似文献
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简要介绍了2-氯-5-氯甲基-1,3-噻唑作为化学原料的应用领域、市场前景、物化性状、其纯化方法。主要介绍了按不同起始原料的多种合成路线并分析其原料来源、合成质量、收率、成本。 相似文献
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以氯乙酸和硫脲为原料合成了2-亚氨基噻唑-4-酮,再与Vilsmeier试剂作用,经缩合水解得到2-氨基4-氯-5-醛基噻唑,总收率达到86%。 相似文献
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Acrylic type polymeric systems having degradable ester bonds linked to 5-aminosalicylic acid were synthesized and evaluated
as materials for drug delivery. 5-Aminosalicylic acid, as an important drug in the treatment of inflammatory bowel diseases,
was linked to 2-hydroxyethyl methacrylate by activated ester methodology in two-step and one-pot procedures to obtain methacryloyloxyethyl
5-amino salicylate. The resulting methacrylic derivative of 5-aminosalicylic acid was copolymerized with methacrylamide, 2-hydroxyethyl
methacrylate and methyl methacrylate (in 1:3 mole ratio) by free radical polymerization method in N,N-dimethylformamide solution, utilizing α,ά-azoisobutyronitrile as initiator at the temperature range of 65–70 °C. The obtained
polymers were characterized by FT-IR, 1H NMR, 13C NMR and elemental analysis. The average molecular weights of the polymers bearing drug units as side substituents of the
acrylic backbone were determined by gel permeation chromatography and their polydispersity indices resulted in the range of
1.6–1.8. Release studies of 5-aminosalicylic acid were performed into dialysis bags by hydrolysis in buffered solutions (pH
1, 7 and 8) at 37 °C. Detection of hydrolysis by UV spectroscopy at selected intervals showed that the drug can be released
by selective hydrolysis of the ester bond at the side of drug moiety. The release profiles indicated that the hydrolytic behavior
of polymeric prodrugs is strongly based on the polymer hydrophilicity and the pH value of the hydrolysis solution. The results
suggest that these systems could be useful for preparation of a controlled release formulation of 5-aminosalicylic acid in
colon. 相似文献
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邻碘苯甲酸及其衍生物是重要的医药化工中间体。为了简化工艺和降低成本,以廉价的苯酐为原料,首先把苯酐在碱性条件下水解为邻苯二甲酸,然后将其与醋酸汞在水中加热回流24 h,得到邻苯二甲酸的汞化物中间体c,粗品收率98%;最后把c与适量碘加入到一定浓度的KI溶液中并回流15 h,酸化,得邻碘苯甲酸,纯品总收率82.5%,熔点164℃。用类似的方法,分别以4-氯苯酐、4-溴苯酐、4-甲氧基苯酐为原料,经水解、汞代和碘代3步得到了相应的产品:5-氯-2-碘苯甲酸、5-溴-2-碘苯甲酸和5-甲氧基-2-碘苯甲酸,纯品总收率分别为65.6%、62.1%、78.2%。在以4-硝基苯酐为原料的合成探索中,没有得到相应的目标产品。各目标产品结构经熔点、1HNMR和IR表征得以证实。邻碘苯甲酸公斤级扩试的结果及收率与小试一致。 相似文献
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以氟乙酸甲酯为原料,在甲醇钠催化下与甲酸乙酯缩合得氟代甲酰乙酸酯烯醇式钠盐(化合物Ⅱ),化合物Ⅱ与O-甲基异脲硫酸盐环合得2-甲氧基-5-氟尿嘧啶(化合物V),V在稀盐酸中水解为5-氟尿嘧啶。在n(氟乙酸甲酯):n(钠):n(甲酸乙酯):n(O-甲基异脲硫酸盐);1.0:3.0:2.5:1.0、缩合温度为35℃、缩合时间为2h、环合温度为40℃、环合时间为6h以及水解温度为60℃的最佳反应条件下,目标化合物总收率为45.3%、纯度大于95%,其结构经IR、1^HNMR确证。 相似文献
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