咪唑及其衍生物的合成研究进展

咪唑及其衍生物作为药物中间体,在生物学、医学、有机化学中占据重要位置.目前咪唑的合成方法主要包括Radziszewski法、Phillips法、溴乙醛法.咪唑衍生物的合成方法主要包括金属催化剂合成法、酸性催化剂合成法、离子液体催化剂合成法等.本文对咪唑及其衍生物的合成方法进行了总结与归纳,并阐述了各种方法的优缺点.     

高效液相色谱法测定咪唑生产工艺中反应液中咪唑及2种杂质2-甲基咪唑和4-甲基咪唑

建立了高效液相色谱(HPLC)外标定量分析咪唑生产工艺中反应液中咪唑及杂质2-甲基咪唑和4-甲基咪唑含量的方法。在色谱分析中,选用Supersil-ODS-B色谱柱为固定相;选用体积比为40∶60的乙腈-离子对试剂(溶液pH为3.5,内含16 mmol·L~(-1)十二烷基硫酸钠和17mmol·L~(-1)磷酸二氢钾)溶液为流动相进行等度洗脱;采用二极管阵列检测器进行检测,检测波长为210nm。结果显示:咪唑、2-甲基咪唑及4-甲基咪唑标准曲线的线性范围均为10～100mg·L~(-1),检出限(3S/N)分别为0.02,0.02,0.03mg·L~(-1)。咪唑在20mg·L~(-1)和100mg·L~(-1)添加水平下的平均加标回收率分别为100%,99.2%,相对标准偏差(n=8)为0.27%。用本方法对同一批反应液不同反应阶段的9个样品中咪唑进行了测定,测定值为10.11%～10.71%;杂质2-甲基咪唑有检出,但低于测定下限;杂质4-甲基咪唑未检出。与气相色谱法进行了比对,两者测定结果基本一致。试验结果表明,该方法准确度好、灵敏度高、重现性好,能够准确测定咪唑生产工艺中反应液中咪唑、2-甲基咪唑及4-甲基咪唑的含量。     

[(dien)Cu(imH)](ClO4)2、[(tren)Cu(imH)](ClO4)2中配位咪唑的离解

本文用紫外可见光谱、pH滴定等方法研究了配合物[(dien)Cu(imH)](ClO₄)₂、[(tren)Cu(imH))(ClO₄)₂中Cu-imH的配位和离解作用,得到了它们的稳定常数,并探索了共存配体的影响。     

HPLC／UV法对银鲫肌肉组织中甲苯咪唑及其代谢产物残留的同时测定

建立了一种用高效液相色谱同时测定银鲫肌肉组织中甲苯咪唑(MBZ)及其代谢物氨基甲苯咪唑和羟基甲苯咪唑的方法.银鲫肌肉组织用乙酸乙酯提取,萃取物旋转蒸发至干后用1 mL二甲基甲酰胺-0.05 mol/L磷酸盐缓冲液(体积比3 ∶ 7)定容.色谱条件:Waters symmetry C18反相色谱柱(250 mm×4.6 mm,5 μm);流动相:乙腈-0.05 mol/L磷酸二氢铵溶液(体积比33 ∶ 67);流速:0.8 mL/min;检测波长为298 nm;检测温度为室温.在10 ～120 μg/kg添加水平,MBZ、MBZ-NH2、MBZ-OH的回收率分别为81% ～86%、71% ～75%、86% ～93%.MBZ的检出限为2 μg/kg,MBZ-OH和MBZ-NH2检出限均为3 μg/kg.     

合成5-氯-1-甲基-4-硝基咪唑的工艺改进

以草酸二乙酯为原料,经酰胺化、环合、成盐及硝化反应合成了5-氯-1-甲基-4-硝基咪唑,总收率61.3%,其结构经1H NMR, IR和MS表征.本方法有两点改进: (1)在酰胺化反应中用30%～40%甲胺水溶液代替甲胺气体; (2)在成盐反应中直接向环化产物的丙酮溶液加硝酸析出5-氯-1-甲基咪唑硝酸盐晶体.     

2,2′-联咪唑合成的改进方法

优化了传统合成及提纯2,2＇-联咪唑的方法,使实验步骤缩减,并使产率和纯度有较大提高。     

螺噻唑并咪唑类化合物的合成

由螺［５．５］十一烷－３－酮与硫脲在碘的存在下反应，生成了４，５－二氢螺［苯并［ｄ］噻唑－６－（７Ｈ），１′－环己烷］－２－胺（３），３与溴甲基苯基甲酮在苯中缩合得到相应的酮４ａ～４ｃ，然后在醇中加热环化生成二氢螺［咪唑并［２，１－ｂ］苯并［ｄ］噻唑］化合物５ａ～５ｃ。新化合物５ａ～５ｃ的分子组成及结构经元素分析、１ＨＮＭＲ、１３ＣＮＭＲ证实，其中产物５ｂ的分子结构经Ｘ－射线衍射晶体分析确认。     

稀土离子的高效毛细管电泳分离和测定

以咪唑为背影为电解质，以乳酸作为络合剂，采用毛细管离子电泳间接紫外法，研究了分离与测定稀土离子的方法，考察了背景电解质酸度、络合剂浓度，背景电解质共存离子的浓度，分离电压对稀土离子的影响。     

左旋咪唑的流动注射在线萃取光度分析研究

本文报道了左旋咪唑的流动注射在线萃取分析研究,采用光度检测法于420nm的波长处测定了左旋咪唑及其制剂的含量。其线性范围为3～30μg/ml,平均回收率为99.5％,相对标准偏差为0.81％。最低检出浓度为0.3μg/ml。方法简便,分析速度可达60次/h,分析结果同标准方法相吻合。     

Synthesis and properties of novel photochromic bisthienylethenes containing imidazole and imidazolium derivatives

A series of bisthienylethenes containing imidazole and imidazolium derivatives have been prepared and the products have been characterized by means of NMR and MS.Their photochromic and fluorescent switch properties have been investigated by UV–vis absorption spectra and fluorescence spectra.The fluorescent emissions of these kinds of photochromic compounds can be simply modulated by varying the imidazole groups,which shows that these compounds may have potential application in the design of fluorescent photochromic materials.     

An efficient synthesis of 5-aminoimidazol-2-ones via cyclization reactions of 2-aminoacetonitriles and isocyanates

The scope of a cyclization reaction between amino-acetonitriles and isocyanates was investigated. The study revealed that this reaction tolerates various functional groups leading to highly functionalized 5-amino-imidazole-2-ones, which are useful intermediates for purine synthesis.     

A Novel Synthesis of Imidazo[1,2-c]pyrimidines

A new method for the preparation of imidazo[1,2-c]pyrimidines is described.     

Palladium-imidazole derivatives as highly active catalysts for Heck reactions

N-Substituted 2-(2-bromophenyl)benzimidazole derivatives have been synthesized and used in palladium catalyzed Heck reactions to give coupled products in good yields.     

On the reactivity of imidazole carbamates and ureas and their use as esterification and amidation reagents

The optimization, substrate scope, and mechanism of esterification and amidation of carboxylic acids mediated by imidazole-based reagents are discussed. The innate reactivity of carbonylimidazole reagents with a range of nucleophiles is also explored. New reagents developed for the synthesis of α,β-unsaturated esters are described, as are reagents for the preparation of tertiary amides directly from carboxylic acids.     

Convenient access to bis-indole alkaloids. Application to the synthesis of topsentins

Topsentins and related bis-indole alkaloids may be efficiently synthesized through an addition/oxidation sequence leading to 2-(3-indolylcarbonyl)-imidazole derivatives followed by a Pd-catalyzed heteroarylation with the appropriate 3-stannylindoles.     

Imidazole-Promoted Synthesis of N-Substituted Phthalimide from N,N′-Disubstituted Ureas in Solventless Conditions

A series of N-substituted phthalimides was synthesized by a thermal reaction between N,N′-disubstituted ureas and phthalic acid catalyzed by imidazole in solventless conditions. The products have been obtained in moderate to good yields (53–92%).

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of 5-amino-2-selenoxo-1,3-imidazole-4-carboselenoamides by the reaction of isoselenocyanates with aminoacetonitriles

Reaction of isoselenocyanates with aminoacetonitriles afforded 4-amino-2-selenoxo-1,3-imidazole-2-selenones, whereas reaction with aminopropionitriles led to selenoureas. We confirmed that it is easy to distinguish between selenoamides and selenoureas by comparison of their chemical shift differences in the ⁷⁷Se NMR spectra.     

Synthesis and characterization of a novel imidazole cyclic trimer

A novel cyclic trimer of imidazole 1, in which imidazole rings are connected by amide bonds, has been synthesized with the help of LiCl as a template for the cyclization. The absorption spectra of 1 indicate the extension of conjugation between imidazole rings and amide bonds. The addition of 3 M equiv of MgCl₂ solubilizes 1 in polar organic solvent, suggesting the chelating ability of 1 to Mg cation.     

Combinatorial Library Synthesis of N‐arylquinoline Derivatives in Aqueous Medium

N‐aryl quinoline derivatives have been prepared by sequential one‐pot reaction of dimedone, aniline, malononitrile and arylaldehydes. The reactions were performed in two different conditions, refluxing in ethanol without catalyst and heating in ethanol/water (1:1) in the presence of imidazole as an organocatalyst. Use of organocatalyst causes shorter reaction times and higher yields.