The Use of Microwave Irradiation for the Rapid Organic Synthesis

Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical importance in chemical reactions. Microwave irradiation has been applied successfully to the areas, such as inorganic synthesis, the prepara-     

Structural Study of Inclusion Complex of Andrographolide with β-Cyclodextrin Prepared under Microwave Irradiation

Andrographolide (Andro) (Figure 1) is a diterpene lactone isolated from Andrographis paniculate Nees1. It has showed several biological activities including analgesic, antipyretic and anti-inflammatory effects2. However, its poor water solubility and unstability towards oxygen restrained its application. In pharmaceutics, b-CD is used to increase solubility and stability3. We have prepared the inclusion compound of Andro/b-CD (Figure 2) under microwave irradiation4. It has been found…     

利用微波辐射制备2-萘甲醚的合成实验

利用微波辐射的方法合成 2 萘甲醚 ,对微波辐射功率、微波辐射时间、催化剂的用量、反应物的配比对反应产率的影响进行讨论 ,该方法与传统合成方法相比具有反应时间短 ,反应条件温和 ,简单易行 ,无污染的特点     

微波促进离子液体相反应在有机合成中的应用

微波促进离子液体相有机合成技术作为一种新型的绿色化学合成法,引起了人们极大的兴趣。在离子液体中,微波辅助下反应快速、收率高、选择性好、后处理简单,离子液体经简单再生后可多次套用。本文综述了以离子液体为反应介质或催化剂的微波辅助技术在多种类型有机反应中的研究成果,主要包括了环合反应、亲核取代反应、金属复分解反应、酰化反应、重排反应、聚合反应、偶联反应、氧化还原反应和选择性脱溴反应等。     

微波与有机化学反应的选择性

本文综述了微波辅助下有机化学反应的选择性,包括化学选择性、区域选择性、顺反选择性、非对映选择性、对映选择性,与传统加热条件下反应选择性的区别。讨论了微波对有机化学反应选择性的影响。从文献报道的结果来看,虽然观察到了一些反应在微波照射与加热条件下显示出不同的选择性,但绝大部分例子并不是在严格相同的条件下进行的对比,还有一些虽然做了对比研究,但却忽略了温度的影响。对于绝大多数例子,微波产生的选择性的差别似乎都可以用热效应来解释。可以认为微波辅助的反应中基本不存在特殊的"非热效应"。微波辅助技术可以通过改变反应温度来实现改变某些反应的选择性。希望本文对微波效应和微波对有机反应加速效应的本质的理解提供一些有用信息。     

Rapid Synthesis of Alkyloxy Porphyrins Under Microwave Irradiation

Alkyloxy porphyrins have been prepared by direct coupling of 5-para-hydroxyphenyl-10,15,20-triphenylporphyrin and alkyl halides under microwave irradiation within several minutes. The length of the alkyl halides has no obvious effect on the yields and reaction time; however, the steric structure of the alkyl halides has a great impact on the reaction time. All the products were confirmed by ¹H NMR.     

Rapid Syntheses of Benzyl Acetate Under Microwave Irradiation

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微波辐射下N-芳基甲酰胺的合成

以甲酸作为甲酰化试剂，通过微波辐射合成的11种N-芳基甲酰胺。产率比传统 方法有所提高，反应时间缩短了20-120倍。     

微波技术在有机合成中的应用

评述了微波加热技术在有机合物的烃基化，酯化和皂化，磺化，烯烃加成，Ｄｉｅｌｓ－Ａｌｄｅｒ缩合，氧化，环化与开环及重排等反应中的应用，参考文献７３篇。     

Rapid Ring‐Opening Reactions of Epoxides using Microwave Irradiation

Copper tetrafluoroborate catalyzes the ring‐opening of epoxides with primary, secondary, and tertiary alcohols in short reaction times under microwave irradiation to give β‐alkoxyalcohol products in excellent yields.     

The Rapid Synthesis of Schiff-Base without Solvent under Microwave Irradiation

The chemistry of the carbon-nitrogen double bond plays a vital role in the progresses of chemistry science1. Schiff-base compounds have been used as fine chemicals and medical substrates. Recently multi-dentate complexes of iron and nickel showed high activities of ethylene oligomerization and polymerization2. In our efforts for ligands of polymerization catalysts, synthesis of Schiff-base through classical condensation of aldehydes (or ketones) and amines were pursued, however, the yield o…     

Rapid Protein Hydrolysis by Microwave Irradiation Using Heat-Resistant Teflon-Pyrex Tubes

A rapid peptide-bond hydrolysis by means of microwave irradiation is introduced for the facile preparation of protein hydrolysates used for amino acid analysis. The optimal hydrolysis condition has been determined using several enzymes with known amino acid compositions. The effects of hydrolysis time on the recovery of various labile and hydrophobic amino acids are also exemplified in the microwave heating of standard amino acids. The method has been applied to the complete amino acid analysis with a single nonvolatile solvent of methanesulfonic acid with good recovery of tryptophan and half-cystine. It provides a radical expedition of protein and peptide hydrolysis via commercial microwave ovens and specially-designed Teflon-Pyrex tubes, circumventing the tedious procedures using vacuum-sealed pyrex lubes heating at 110°C for more than 24 h. This novel type of microwave chemistry associated with rapid peptide-bond cleavage is of great potential in the automation of the complete process of amino acid analysis starting from the preparation of protein hydrolysates.     

微波辐射下的1,4-二甲基咔唑-9-羧酸的快速合成

以ＤＭＦ为溶剂,在微波辐射下由１,４－二甲基咔唑和相应的溴酯快速合成了两种１,４－二甲基咔唑－９－羧酸化合物,在最佳反应条件下,产率分别为８５．２％和８３．１％。     

A Rapid and Convenient Synthesis of Derivatives of Imidazoles under Microwave Irradiation

An efficient and a quick microwave‐assisted synthesis of benzimidazoles and trisubstituted imidazoles was developed. Three benzimidazoles were obtained as a result of the condensation of 1,2‐phenylenediamine with carboxylic acids and acetoacetic ester without catalyst. A series of trisubstituted imidazoles were synthesized by condensation of benzil, aromatic aldehyde and ammonium acetate in the presence of glacial acetic acid.     

A Critical Overview on the Effect of Microwave Irradiation in Organic Synthesis

Despite the great success of Microwave Assisted Organic Synthesis (MAOS) there is still a lack of knowledge about the interaction of the electromagnetic radiation with matter. In consequence, it has been very difficult to rationalize the effect of microwave irradiation in chemistry, to determine the existence of microwave effects (thermal and non‐thermal) and to develop predictive models on the characteristics required for a reaction to be improved under microwaves. This has been a handicap to develop new chemistry under microwave irradiation and the origin of many controversies. This personal account collects some new findings in this field and our work on the use of computational chemistry to develop predictive models and to determine parameters related to thermal and non‐thermal effects, with clear advantages over experimental methods where separation of these effect is almost impossible.     

Solvent-free Rapid Synthesis of Styryl Dyes with Benzimidazole Nucleus Using Microwave Irradiation

The reactions of 2-methylbenzimidazole or 2-methylbenzimidazolium iodide with aromatic aldehydes are accelerated under microwave irradiation by using Ac2O or piperidine as dehydrant or catalyst in the absence of any solvent. The approach provides an attractive and environmentally friendly pathway to several useful styryl dyes with benzimidazole nucleus.     

Rapid and Convenient Synthesis of N‐Arylmorpholines under Microwave Irradiation

A series of N‐arylmorpholines 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h , 1i , 1j , 1k , 1l , 1m , 1n was obtained by cyclocondensation of arylamines and diethylene glycol dimesylate under microwave irradiation in an aqueous potassium carbonate medium. The reaction is rapid and convenient, and a variety of functional groups are tolerated in the process.     

XC-72碳和碳纳米管负载PtRu纳米粒子的微波快速合成及其对甲醇的电化学氧化

利用微波辐射加热技术快速合成了XC-72碳和碳纳米管(CNTs)负载的PtRu合金纳米粒子,合金负载的质量分数为20%,Pt和Ru的原子比接近于1:1.透射电镜观察表明微波合成的PtRu合金纳米粒子具有细小的粒径和狭窄的尺寸分布,所合成的PtRu合金纳米粒子高度分散在XC-72碳和CNTs的表面,其平均粒径分别为3.3 nm和2.8 nm.电化学实验表明微波合成的PtRu/XC-72和PtRu/CNTs纳米催化剂比用湿化学方法以KBH₄还原制备的催化剂对甲醇的电化学氧化具有更高的催化活性.     

微波辐射技术在活性炭制备中的应用

对微波辐射技术在活性炭的活化、表面改性及再生过程中的研究进展进行了概述。微波功率是影响活性炭的活化、改性、再生及其吸附性能和得率的主要因素之一。众多实验结果表明,微波辐射技术是制备活性炭材料和提高活性炭吸附性能的有效途径。