二醋酸碘苯促进苯并咪唑类化合物的合成

二醋酸碘苯促进下, 由邻苯二胺或4-甲基邻苯二胺与各种芳醛通过一步反应合成了13种苯并咪唑类化合物, 反应时间3～5 min, 反应产率83%～98%, 用核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征. 该合成方法具有底物适用范围广、反应条件温和、反应速度快、反应产率高的优点. 根据实验结果对该反应提出了可能的反应机理.     

苯并咪唑开环反应研究

本课题组曾首次报道过咪唑啉的还原开环反应[1],2-烷基-2-咪唑啉在硼氢化钠作用下生成开环产物--乙二胺衍生物.通过对这一新反应的研究,提出了通过咪唑啉制备N-取代乙二胺、N,N-二取代乙二胺、4-取代二亚乙基三胺等乙二胺衍生物简便的新合成方法.在此基础上,我们对苯并咪唑衍生物进行了类似的反应研究,希望通过其开环反应制备N-取代邻苯二胺、N,N'-多取代邻苯二胺衍生物.     

碘促进的苯并咪唑及其衍生物的合成

在碘的氧化作用下,由伯醇和邻苯二胺一步合成了苯并咪唑及其衍生物。考察了碘和碳酸钾用量及温度对反应产率的影响,反应较佳的条件为n(o-ClC6H4CH2OH)∶n(o-phenylenediamine)∶n(I2)∶n(K2CO3)=1.0∶1.1∶5.0∶5.0,反应温度70℃,反应时间5 h。用方法A在较佳的反应条件下2-(2-氯苯基)苯并咪唑的产率可达86%,用方法B其产率达69%。没有选择传统的醛或酸作为反应底物,而是选择了伯醇在碘的氧化作用下直接合成了目标产物,反应为合成苯并咪唑及其衍生物的一个新方法,探讨了可能的反应机理。     

8,10-二氢-7H-4b,8,10-三氮杂苯薁衍生物的合成

苯并咪唑类化合物具有广泛的生物活性,其合成和应用研究一直十分活跃.以2-氨甲基苯并眯唑二盐酸盐与α,β-不饱和酮在三乙胺存在下,以正丁醇为溶剂反应,合成了4种8,10-氢-7H-4b,8,10-三氮杂苯并奠类衍生物,产率61%～67%.反应产物结构通过NMR、MS、元素分析和IR表征.     

四溴化碳促进下2-(1H-苯并[d]咪唑)-3-芳基丙烯腈的高效合成

2-苯并咪唑-3-芳基丙烯腈衍生物具有广谱的生物活性,同时还是一类重要的合成中间体,在有机合成领域具有广泛的应用.以芳醛和2-氰甲基苯并咪唑为原料,乙醇为溶剂,在四溴化碳促进下,高效合成了2-(1H-苯并[d]咪唑)-3-芳基丙烯腈.反应在回流条件下搅拌5～10 min即可完成,以74%～96%的产率得到目标产物.该方法为2-苯并咪唑-3-芳基丙烯腈衍生物的制备提供了反应条件温和、后处理方便和底物适用范围广的合成策略.     

铜催化串联C-H官能化反应构建苯并咪唑稠合二氢苯并唑类化合物

苯并咪唑稠合二氢苯并唑是一类复杂的氮氧杂环,在生物医药和功能性材料中具有较高的应用价值.本文在空气氛围中以苯并咪唑和2-溴苯酚为原料、廉价Cu(Ⅱ)为催化剂,采用"一锅法"合成了苯并咪唑稠合二氢苯并唑类化合物,反应经历了N-芳基化、sp~2 C-H活化、C-O环化的串联过程.研究表明,该反应对于苯并咪唑类衍生物,以及其他反应底物(如2-碘苯酚和2-羟基苯硼酸)均具有一定的官能团耐受性.本文为高效合成苯并咪唑稠合二氢苯并唑类化合物提供了一种简便方法.     

4种氮杂双环化合物的合成方法改进

以邻苯二胺及2,3-二氨基吡啶为原料,与羰基化合物反应制备苯并吡嗪、吡啶并吡嗪、苯并咪唑和吡啶并咪唑4种氮杂双环化合物,探讨了溶剂、温度、时间和pH值等实验条件对反应的影响。 在合成吡啶并吡嗪时,采用正丙醇为溶剂,用甲醇钠调节pH=9,回流反应1 h,将收率从35.7%提高至89.4%;在合成苯并吡嗪时,用水作溶剂,用亚硫酸钠调节pH=9,60 ℃反应40 min,产物纯化采用低温静置代替减压蒸馏,收率可提高至98.3%;尝试不同方法合成苯并咪唑和吡啶并咪唑,确定最优合成条件分别为：邻苯二胺在88%的甲酸溶液中回流2 h,苯并咪唑收率为92%;2,3-二氨基吡啶在原甲酸三已酯中回流3 h,加浓盐酸继续回流1 h,吡啶并咪唑收率为84.2%。     

苯并咪唑衍生物的合成改进

利用空气作氧化剂, 无需任何催化剂, 以甲醇作溶剂, 芳香醛与邻苯二胺反应一步合成苯并咪唑衍生物, 产率均超过69%, 产物的结构通过元素分析、红外光谱和核磁共振氢谱确证, 该方法具有操作简单、反应条件温和、环境友好的优点.     

2,5′-双苯并咪唑衍生物的合成

以二乙酰氧基碘苯为氧化剂，对邻苯二胺衍生物的席夫碱进行分子内脱氢环全反应，生成新化合物5－[5-(4-甲基－1－哌嗪基）－1H－苯并咪唑基]-2-(4-吡啶基）－1H－苯并咪唑，该反应不仅条件温和、反应迅速，产率良好，而且操作简便安全，所得产物及中间体均经1H NMR，FT－IR以及元素分析表征。     

含咔唑基苯并咪唑衍生物的合成

以咔唑为原料,经烷基化、甲酰化反应合成N-烃基咔唑-3-甲醛;无催化剂条件下,N-烃基咔唑-3-甲醛与邻苯二胺经缩合-环化"一锅"反应合成了两类新型含咔唑单元的苯并咪唑衍生物.研究了溶剂选择、溶剂用量、反应温度、反应物配比等因素对缩合-环化反应结果的影响;通过改变两种反应物的等物质的量比可选择性地得到以其中一类苯并咪唑衍生物为主的产物.     

A FACILE PREPARATION OF 3-HALOFLAVONES USING HYPERVALENT IODINE* CHEMISTRY

Various 3-haloflavones were prepared by the reaction of the corresponding flavone derivatives with iodobenzene diacetate and trimethylsilyl halide under mild reaction conditions. The iodobenzene diacetate could be replaced by the polymer supported iodobenzene diacetate without the decreasing activity.

     

Novel trialkylsilyl(germyl)-substituted thienyl- and furylbenzimidazoles and their N-substituted derivatives – synthesis,structure and cytotoxic activity

The reaction of 1,2-phenylenediamine with a variety of silicon- or germanium-containing 2-furaldehydes or 2-thienylcarbaldehydes in DMFA gave the corresponding benzimidazole derivatives in moderate yields (36–49%) in the presence of sodium hydrogen sulfite. As a result, a new series of silyl, germyl substituted hetarylbenzimidazoles were synthesized and their in vitro cytotoxicity was studied. The quaternisation of N-substituted benzimidazoles by heating with various alkyl, allyl and propargyl chlorides and bromides leads to the formation of benzimidazolinium salts. Potential cytotoxic activity of synthesized new benzimidazoles and benzimidazolinium salts was tested in vitro on two monolayer tumour cell lines: MG-22A (mouse hepatoma), HT-1080 (human fibrosarcoma) and normal mouse fibroblasts (NIH 3T3) and compared with corresponding benzimidazoles.     

Hypervalent Iodine in Synthesis. 90. A Mild and Efficient Method for the Iodination of Pyrazoles

Abstract

The combined reagent of iodobenzene diacetate (or polymer-supported iodobenzene diacetate) with iodine was used as an effective iodinating agent of pyrazoles to the corresponding 4-iodopyrazole derivatives at room temperature with high yields.     

Synthesis of new 1‐phenylthieno[1,2,4]triazolo[4,3‐a]pyrimidin‐5(4H)‐one derivatives

A series of novel 1‐phenylthieno[1,2,4]triazolo[4,3‐a]pyrimidin‐5(4H)‐one derivatives 5 and 6 were synthesized by oxidative cyclization of thienopyrimidinonyl hydrazones using iodobenzene diacetate. J. Heterocyclic Chem., (2011).     

Borane complexes of 2-(1-Methyl-1,2,5,6-tetra-hydropyridin-3-yl)benzoxazoles

2-Pyridin-3-ylbenzoxazoles were synthesized by the reaction between 3-pyridinecarboxaldehyde and substituted o-aminophenols in the presence of iodobenzene diacetate. The resulting benzoxazoles 3 were treated with methyl iodide to give the corresponding pyridinium salts 4 which underwent the hydride reduction with sodium borohydride or sodium cyanoborohydride to produce 2-(1-methyl-1,2,5,6-tetrahy-dropyridin-3-yl)benzoxazole borane complex derivatives.     

Research on imidazo[1,2-a]benzimidazole derivatives XII. 3-Acyl-substituted imidazo[1,2-a]benzimidazoles

Stable 3-acetyl derivatives of imidazo[1,2-a]benzimidazole were synthesized by the action of acetic anhydride on 2,9-disubstituted imidazo[1,2-a]benzimidazole. The former were also obtained by cyclization of 1-alkyl (aralkyl) -3-acylmethyl-2-iminobenzimidazoline hydrobromides in acetic anhydride in the presence of anhydrous sodium acetate. 3-Benzoyl-substituted imidazo[1,2-a]benzimidazoles, which are unstable in acidic media, were synthesized by the action of benzoyl chloride in the presence of pyridine or excess starting imidazo [1,2-a] benzimidazole.See [1] for communication XI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 121– 125, January, 1976.     

Synthesis and Antimicrobial Screening of 2‐Aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole Derivatives

A new series of 2‐aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole derivatives was synthesized by condensation of 2‐(2‐substituted thiazol‐4‐yl)acetohydrazide with aryl aldehydes followed by oxidative cyclocondensation using iodobenzene diacetate. The structure of synthesized compounds was characterized by IR, NMR, and mass analysis. All the newly synthesized compounds were evaluated for their in vitro antimicrobial activity. Some of the compounds showed moderate antimicrobial activity.     

Synthesis of 2‐(1‐methyl‐1,2,5,6‐tetrahydropyridin‐3‐yl)benzimidazoles

A useful approach for the synthesis of pharmacologically active tetrahydropyridinylbenzimidazoles is described. 2‐Pyridin‐3‐ylbenzimidazoles 3a‐d have been synthesized by condensation of 3‐pyridinecarbox‐aldehyde 1 with substituted 1,2‐phenylenediamines 2a‐d following oxidative cyclization with iodobenzene diacetate. Methylation of 3a‐d with iodomethane and potassium hydroxide, subsequent formation of methylpyridinium salts 4a‐d and 7a‐d and reduction thereafter afforded tetrahydropyridinylbenzimidazoles 5a‐d and 8a‐d .     

Biphenylenes—XXX: Synthesis and some reactions op 5,10-diazabenzo[b]biphenylenes

Condensation of benzocyclobutene-1,2-dione with 10 derivatives of o-phenylenediamine gave the corresponding benzo-substituted derivatives of 5,10-diazabenzo[b]biphenylene. Attempted oxidative demethylation of 2,3-dimethoxy-5,10-diaza benzo[b]biphenylene gave 2-methoxy-5-phthalimido benzo-1,4-quinone. Other attempts to demethylate methoxy diazabenzobiphenylenes are described. 5,10-Diazabenzo[b]biphenylene was not oxidised by air, lead tetra-acetate, or phenyliodoso diacetate, but with peracetic acid it gave dibenzodiazocine-5,12-dione and o-nitroaniline. Reduction of the diazabiphenylene with Raney nickel gave 2-phenylquinoxaline. The diazabiphenylene is readily hydrolysed by nitric and hydrochloric acid to regenerate benzocyclobutene-1,2-dione and o-phenylenediamine which then recondense to give a mixture of products. A similar hydrolysis occurs with sodium hydroxide