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1.
反相高效液相色谱分离红霉素肟的醚化产物的构型异构体 总被引:2,自引:0,他引:2
1 引 言克拉霉素 (clarithromycin)是第二代大环内酯类抗生素 ,是红霉素A的 6 OH的甲基化衍生物。主要合成途径是红霉素A经肟化、醚化、硅烷化保护 ,再选择性甲基化 ,最后脱保护、脱肟而制得。其中肟羟基的醚化保护是实施工艺改进最关键的一步。我们采用 1 乙氧基环己烯为醚化试剂 ,对克拉霉素进行了合成新工艺的研究 ,取得重要突破。由于红霉素肟(oxime)有两种异构体 ,相应的其醚化产物 (ECHoxime)也有两种构型异构体 :(E) 红霉素A 9 (1 乙氧环己基 )肟和(Z) 红霉素A 9 (1 乙氧环己基 )肟 ;另外产品中还有原料带进的工艺杂质… 相似文献
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克拉霉素在不同条件下水解,分别生成3-羟基克拉霉素(2)和3-羟基-8,9,10,11-二脱水-9,12-半缩酮克拉霉素(3),用乙酸酐保护2的C(2')-OH得到2'-乙酰基-3-羟基克拉霉素(4),用Ⅳ-氯代琥珀酰亚胺(NCS)氧化4的C(3)-OH合成了2'-乙酰基-3-氧代克拉霉素(5),采用MS,IR,1H NMR,13C NMR等对这些化合物进行了表征.用X射线单晶衍射法测定了化合物2和5的晶体结构,其均属于正交晶系,P212121空间群.化合物2的晶胞参数a=1.3657(3)nm,6=1.4783(3)nm,c=1.6510(3)nm,Z=4,V=3.3332(12)am3,Dc=1.175 g/cm3,F(000)=1288,μ=0.087mm-1;化合物5的晶胞参数a=1.5124(3)nm,b=1.5247(3)nm,c=1.5288(3)nm,Z=4,V=3.5254(12)nm3,Dc=1.187g/cm3,F(000)=1368.0,μ=0.088 mm-1. 相似文献
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克拉霉素在不同条件下水解, 分别生成3-羟基克拉霉素(2)和3-羟基-8,9,10,11-二脱水-9,12-半缩酮克拉霉素(3), 用乙酸酐保护2的C(2’)-OH得到2′-乙酰基-3-羟基克拉霉素(4), 用N-氯代琥珀酰亚胺(NCS)氧化4的C(3)—OH合成了2’-乙酰基-3-氧代克拉霉素(5), 采用MS, IR, 1H NMR, 13C NMR等对这些化合物进行了表征. 用X射线单晶衍射法测定了化合物2和5的晶体结构, 其均属于正交晶系, P212121 空间群. 化合物2的晶胞参数a=1.3657(3) nm, b=1.4783(3) nm, c=1.6510(3) nm, Z=4, V=3.3332(12) nm3, Dc=1.175 g/cm3, F(000)=1288, μ=0.087 mm-1; 化合物5的晶胞参数 a=1.5124(3) nm, b=1.5247(3) nm, c=1.5288(3) nm, Z=4, V=3.5254(12) nm3, Dc=1.187 g/cm3, F(000)=1368.0, μ=0.088 mm-1. 相似文献
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克拉霉素在不同条件下水解,分别生成3-羟基克拉霉素(2)和3-羟基-8,9,10,11-二脱水-9,12-半缩酮克拉霉素(3),用乙酸酐保护2的C(2’)-OH得到2’-乙酰基-3-羟基克拉霉素(4),用N-氯代琥珀酰亚胺(NCS)氧化4的C(3)-OH合成了2’-乙酰基-3-氧代克拉霉素(5),采用MS,IR,^1H NMR,^13C NMR等对这些化合物进行了表征.用X射线单晶衍射法测定了化合物2和5的晶体结构,其均属于正交晶系,P212121空间群.化合物2的晶胞参数a=1.3657(3)nm,b=1.4783(3)nm,c=1.6510(3)nm,Z=4,V=3.3332(12)nm^3,Dc=1.175g/cm^3,F(000)=1288,/t=0.087mm^-1;化合物5的晶胞参数a=1.5124(3)nm,b=1.5247(3)nm,c=1.5288(3)nm,Z=4,V=3.5254(12)nm^3,Dc=1.187g/cm^3,F(000)=1368.0,μ=0.088mm^-1. 相似文献
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6.
克拉霉素的合成新方法 总被引:5,自引:0,他引:5
以醚化剂1-乙氧基环己烯和硅烷化试剂1,1,1,3,3,3-六甲基二硅氨烷为保护试剂, 采用醚化-硅烷化保护法制备了克拉霉素. 以红霉素A肟为原料计算, 经肟羟基醚化、2',4"-OH硅烷化、6-OH选择性甲基化、脱保护至克拉霉素, 四步反应总收率为49.5%. 相似文献
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柱前衍生高效液相色谱法测定血清中克拉霉素的含量 总被引:3,自引:0,他引:3
建立了2,4-二硝基苯肼柱前衍生反相高效液相色谱紫外检测法测定血清中克拉霉素的含量,将在碱性条件下甲基叔丁基醚的血清萃取物,与2,4-二硝基苯肼在55%酸性条件下反应30min,然后用乙腈-0.05mol/LpH7.2磷酸盐缓冲液(48:52)在Alltima C18色谱柱上进行分离,在340nm检测衍生物。方法的线性范围为0.05~3.2mg/L(r=0.9993);检出限为30μg/L,绝对回收率大于89%,相对标准差小于10%。本方法已用于克拉霉素在健康受试者中的药代动力学研究。 相似文献
11.
Neufeind S Hülsken N Neudörfl JM Schlörer N Schmalz HG 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(9):2633-2641
The structurally unique polyketide mumbaistatin is the strongest naturally occurring inhibitor of glucose-6-phosphate translocase-1 (G6P-T1), which is a promising target for drugs against type-2 diabetes mellitus and angiogenic processes associated with brain tumor development. Despite its high relevance, mumbaistatin has so far withstood all attempts towards its total synthesis. In the present study an efficient total synthesis of a deoxy-mumbaistatin analogue containing the complete carbon skeleton and a spirolactone motif closely resembling the natural product in its cyclized form was elaborated. Key steps of the synthesis are a Diels-Alder cycloaddition for the construction of the fully functionalized anthraquinone moiety and an anionic homo-Fries rearrangement to build up the tetra-ortho-substituted benzophenone core motif, from which a spiroketal lactone forms in a spontaneous process. The elaborated strategy opens an entry to a variety of new analogs of mumbaistatin and cyclo-mumbaistatin and may be exploited for the total synthesis of the natural product itself in the future. 相似文献
12.
Dennis P. Curran 《Angewandte Chemie (International ed. in English)》1998,37(9):1174-1196
A dirty word in synthesis: separation! The normally unavoidable separation at the end of each reaction finds no friends among synthetic chemists and is often regarded as a technical procedure. However, the need to quickly and cheaply produce pure products is driving the development of new separation and purification techniques. Astonishingly, the modern concepts and techniques for coupling synthesis and separation are rooted in workup procedures that are as old as the art of synthesis itself. 相似文献
13.
氨合成催化剂100年:实践、启迪和挑战 总被引:2,自引:0,他引:2
Haber-Bosch发明的氨合成催化剂创立已经100周年. 介绍了氨合成催化剂在理论和实践方面的发展、成就及其启迪,展望了氨合成催化剂的未来和面临的新挑战. 催化合成氨技术在20世纪化学工业的发展中起着核心的作用. 一个世纪以来,氨合成催化剂经历了Fe3O4基熔铁催化剂、Fe1-xO基熔铁催化剂、Ru基催化剂等发展阶段,以及钴钼双金属氮化物催化剂的发现. 实践表明,氨合成催化剂是多相催化领域中许多基础研究的起点和试金石,没有别的反应象氨合成反应一样,能够把理论、模型催化剂和实验连接起来. 催化合成氨反应仍然是多相催化理论研究的一个理想的模型体系. 理解该反应机理并转换成完美技术成为催化研究领域发展的基本标准. 这个永不结束的故事仍然没有结束. 除了关于反应的基本步骤、真实结构、亚氮化物这些问题之外,催化合成氨在理论上一个新的挑战是关于在室温和常压下氨合成的预测,包括电催化合成氨、光催化合成氨和化学模拟生物固氮以及包括氮分子在内的催化化学研究中几种最稳定的小分子的活化方法等. 相似文献
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McIntyre BG Martínez Bermejo F Srivastava SK Husbands SM Lewis JW Crosby J Simpson TJ 《Combinatorial chemistry & high throughput screening》2001,4(1):111-114
Synthesis of 4-hydroxycinnamic acid 6 and its N-hydroxysuccinimide ester 8 has been carried out in high yield on solid support. Further development allowed the synthesis of 4-hydroxycinnamoyl CoA 1 in excellent overall yield. The utility of solid phase as a method for the synthesis of 4-hydroxycinnamic acid derivatives was demonstrated by the synthesis of a number of compounds including the NMDA receptor antagonists, N-(phenylalkyl)cinnamides 9 and 10. 相似文献
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固相有机合成研究进展 总被引:4,自引:0,他引:4
组合化学技术给固相有机合成带来了新的发展契机,同时也提出了新的发展要求。目前这一研究领域发展迅速,应用范围不断扩大,技术日臻完善。本文综述了近期固相有机合成研究方面的最新进展。 相似文献
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Polyaniline (PANI) is one of the most extensively used conducting polymer due to its fascinating properties including conducting, thermal, optical, magnetic and electrochemical properties, simple synthesis procedure and low cost of monomer. It has attracted major attention in a variety of applications including electrochemical sensors, catalysts, supercapacitors and biosensors. However, its limitations such as insolubility in common solvents, low process-ability and poor mechanical properties have led to the development of new approaches to improve it properties. Metal nanoparticles (MNPs) such as silver, gold, copper and palladium have been combined with PANI to improve on its properties which has led to a new class of materials known as metal/PANI nanocomposites. These hybrid nanocomposites incorporate advantages of both MNPs and polymers which effectively improves the properties of the individual materials. Various synthesis techniques including in situ polymerization, ɤ-radiolysis, electrodeposition, complexation, vacuum deposition and interfacial polymerization have been used in the formation of metal/PANI nanocomposites. These nanocomposites have been used in various sensor and biosensor applications due to their excellent conductivity, ease of synthesis, excellent redox potentials, chemical and thermal stability. This review highlights the various metal/PANI nanocomposites, their various synthesis techniques and their application in sensors and biosensors. The importance of these nanocomposites in sensing and signaling various toxic heavy metals such as mercury, lead and silver and toxic gases such as hydrogen sulphide, ammonia and chloroform has been discussed. In addition the review covers the applications of metal/PANI nanocomposites in biosensor systems for the detection of glucose, DNA, protein, cholesterol, drugs and hydrogen peroxide. 相似文献
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Daniele Aiello Hendrik Jonas Anna Carbone Daniela Carbone Camilla Pecoraro Luisa Tesoriere Jens Khler Bernhard Wünsch Patrizia Diana 《Molecules (Basel, Switzerland)》2022,27(21)
Natural products are an excellent source of inspiration for the development of new drugs. Among them, betalains have been extensively studied for their antioxidant properties and potential application as natural food dyes. Herein, we describe the seven-step synthesis of new betalamic acid analogs without carboxy groups in the 2- and 6-position with an overall yield of ~70%. The Folin–Ciocalteu assay was used to determine the antioxidant properties of protected intermediate 21. Additionally, the five-step synthesis of betalamic acid analog 35 with three ester moieties was performed. Using NMR techniques, the stability of the obtained compounds towards oxygen was analyzed. 相似文献
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A regiodivergent synthesis of ring a C-prenylflavones 总被引:1,自引:0,他引:1
Capitalizing on the use of orthogonal protecting groups and the development of a modified Robinson flavone synthesis that avoids harsh acidic conditions, a regioselective synthesis of 6- and 8-prenylflavones from the same prenylated disilylated phloracetophenone (9) has been developed, targeting cannflavin B (1d), the COX-inhibiting principle of marijuana, and its unnatural isomer isocannflavin B (1e) as model compounds. 相似文献
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无水烟酸锂的合成、结构表征及热化学性质 总被引:1,自引:0,他引:1
选择分析纯烟酸和一水氢氧化锂为反应物, 利用水热合成方法合成了无水烟酸锂. 利用FTIR和X射线粉末衍射等方法表征了它的结构. 用精密自动绝热热量计测定了它在78~400 K温区的低温热容, 将该温区的摩尔热容实验值用最小二乘法拟合, 得到热容随温度变化的多项式方程. 用此方程进行数值积分, 得到温区内每隔5 K的舒平热容值和相对于298.15 K时的各种热力学函数值. 在此基础上, 通过设计合理的热化学循环, 利用等温环境溶解-反应热量计分别测定该反应的反应物和生成物在所选溶剂中的溶解焓, 从而得到此反应的反应焓为: =-(20.21±0.41) kJ8226; mol-1. 最后, 依据Hess定律计算出无水烟酸锂的标准摩尔生成焓为: [Li(C6H4NO2), s]=-(278.29±1.01) kJ8226;mol-1. 相似文献
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Albelda MT García-España E Jiménez HR Llinares JM Soriano C Sornosa-Ten A Verdejo B 《Dalton transactions (Cambridge, England : 2003)》2006,(37):4474-4481
The synthesis, characterization, Cu2+ coordination and interaction with AMP of three tripodal polyamines are reported. The polyamines are based on the structure of the tetraamine (tren) which has been enlarged with three propylamino functionalities (), with a further anthrylmethyl fragment at one of its terminal primary nitrogens () or with naphthylmethyl fragments at its three ends (). The protonation constants of all three polyamines show that at pH 6, all six primary and secondary nitrogen atoms in the arms are protonated. The interaction with Cu2+ and AMP (adenosine-5'-monophosphate) has been studied by potentiometric, UV-Vis, ESI-MS spectroscopy and NMR techniques. pH-Metric, NMR and ESI/MS techniques indicate that and form with AMP adducts of 1:1, 2:1 and 3:1 AMP:L stoichiometries in water. This is one of the first examples for the formation of such complexes in aqueous solution. Formation of ternary complexes between , , , Cu2+ and AMP is observed. Paramagnetic NMR techniques have been used to obtain structural information on the binding mode of AMP to the Cu2+- binuclear complexes. 相似文献