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Microwave-assisted C-C, C-O, C-N, C-S bond formation and multicomponent reactions using magnetic retrievable nanocatalysts 使用磁性可回收纳米催化剂的微波辅助C-C、C-O、C-N、C-S键的形成和多组分反应
IF 0.8 Pub Date : 2021-08-04 DOI: 10.2174/2213335608666210804144559
Manavi Yadav, Mahima Dutta, Pema Tanwar, Reena Jain, Anju Srivastava, Ranjan Sharma
Microwave-assisted organic synthesis has been perceived as one of the most powerful and sustainable tools to accomplish expeditious organic synthesis through a greener way on account of its specific features including targeted heating, reaction homogeneity, rapidity, possible modifications of activation parameters, improved selectivity, yield and purity, along with simpler work-up. Another rapidly growing field for the development of green and sustainable protocol is the application of the magnetic nanocatalysts. They not only meet the need for facile recovery from the reaction media after completion of a reaction but also provide the best attributes of nanotechnology along with the elimination of auxiliary substances and catalyst loss, thereby, making the overall process clean, fast and cost-effective. Thus, the amalgamation of magnetic nanocatalysts and microwave irradiation present an ideal blend for the development of sustainable methods in synthetic organic chemistry. Amidst various bond forming reactions, carbon-carbon (C–C) and carbon-heteroatom (C-X, where X= O, N, S) bond formations are essentially used to devise privileged molecular scaffolds for synthetic organic and medicinal chemistry. This review gives a succinct overview of the synthesis and application of various modified magnetic nanocomposites as task-specific catalysts for microwave assisted C-C and C-X bond formation reactions in recent years. (This review consists of more than 190 references)
微波辅助有机合成被认为是通过更环保的方式实现快速有机合成的最强大和可持续的工具之一,因为它的具体特征包括有针对性的加热、反应均匀性、快速性、活化参数的可能修改、提高的选择性、产率和纯度,以及更简单的后处理。开发绿色和可持续协议的另一个快速增长的领域是磁性纳米催化剂的应用。它们不仅满足了在反应完成后从反应介质中容易回收的需求,而且还提供了纳米技术的最佳特性,同时消除了辅助物质和催化剂损失,从而使整个过程清洁、快速且具有成本效益。因此,磁性纳米催化剂和微波辐射的融合为合成有机化学中可持续方法的发展提供了理想的混合物。在各种成键反应中,碳-碳(C–C)和碳杂原子(C-X,其中X=O,N,S)键的形成基本上用于设计合成有机和药物化学的特殊分子支架。本文简要综述了近年来各种改性磁性纳米复合材料的合成及其在微波辅助C-C和C-X键形成反应中的应用。(本综述由190多篇参考文献组成)
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引用次数: 2
Meet The Editorial Board Member 见见编委会成员
IF 0.8 Pub Date : 2021-08-01 DOI: 10.2174/221333560802211028163158
D. Bogdał
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引用次数: 0
Microwave-assisted Carbon-Carbon and Carbon-Heteroatom Bond Forming Reactions - Part 2A (Part 1) 微波辅助碳-碳和碳-杂原子键形成反应.第2A部分(第1部分)
IF 0.8 Pub Date : 2021-08-01 DOI: 10.2174/221333560802211028163413
B. Banerjee
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引用次数: 0
Preface 前言
IF 0.8 Pub Date : 2021-07-13 DOI: 10.2174/221333560801210603090513
Jerry J. Wu
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引用次数: 0
Meet The Editorial Board Member 见见编委会成员
IF 0.8 Pub Date : 2021-07-13 DOI: 10.2174/221333560801210603090602
Elisabete Clara Bastos Do Amaral Alegria
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引用次数: 0
Microwave-assisted organic synthesis in Water 微波辅助水中有机合成
IF 0.8 Pub Date : 2021-06-23 DOI: 10.2174/2213335608666210623151121
Geetanjali, Ram Singh
Most of the traditional methods for organic synthesis have been associated with environmental concern. The transition from traditional to modern methods of synthesis is mainly based on principles of green chemistry to achieve better sustainability by reducing the negative impact on the environment and health. It has been found that microwaves as an energy source in organic synthesis have a great advantage over conventional heating. Microwave-assisted reactions are energy efficient and hence, brought themselves in the preview green chemistry principles. The use of safer solvents is another important principle of green chemistry. The use of water as a solvent in organic synthesis has great benefits over the use of hazardous organic solvents in terms of environment and safety. This study will cover the use of both microwave and water simultaneously in organic reactions.
大多数传统的有机合成方法都与环境问题有关。从传统合成方法向现代合成方法的转变主要基于绿色化学原理,通过减少对环境和健康的负面影响来实现更好的可持续性。已经发现微波作为有机合成中的能量源比传统加热具有很大的优势。微波辅助反应是节能的,因此被纳入了绿色化学原理的预览。使用更安全的溶剂是绿色化学的另一个重要原则。在环境和安全方面,在有机合成中使用水作为溶剂比使用危险的有机溶剂具有很大的益处。这项研究将涵盖在有机反应中同时使用微波和水。
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引用次数: 3
Synthesis and Pharmacological Activities of Oxadiazole and Pyrimidine Bearing Thiocoumarin Derivatives 含恶二唑和嘧啶硫代香豆素衍生物的合成及其药理活性
IF 0.8 Pub Date : 2021-04-01 DOI: 10.2174/2213335608666210401152153
Monika R. Tiwari, N. Patel
The study aims to synthesize thiocoumarin scaffolds clubbed with pyrimidineand 1,3,4-oxadiazole ring system under microwave irradiation and describe their pharmacologicalactivities.We report herein an efficient and simple Lewis acid-catalyzed procedure for thesynthesis of novel series of thiocoumarin clubbed with pyrimidine and 1,3,4-oxadiazole motifsunder microwave irradiation. The microwave-assisted technique has many advantages, such as ahigher yield, a clean and selective procedure, shorter reaction time, and simple work-up.The objective of the present study is to design and synthesize thiocoumarin scaffoldsclubbed with pyrimidine and 1,3,4-oxadiazole ring system by microwave-assisted heating. Ourprime focus is to highlight the synthetic approach developed for the synthesis of heterocyclic moietiesof pharmacological interest, and the prominence has also been given to distinct advantagesprovided by microwave heating. Thiocoumarin clubbed with pyrimidine, and 1,3,4-oxadiazole motifs was synthesizedunder microwave irradiation. All the synthesized molecules were evicted by IR, 1H NMR, 13CNMR, and mass spectra. The anti-microbial activity of synthesized compounds was examinedagainst two Gram-negative bacteria (E. coli, P. aeruginosa), two Gram-positive bacteria (S. aureus,S. pyogenes), and three fungi (C. albicans, A. niger, A. clavatus) using the MIC (Minimal InhibitoryConcentration) method, anti-tubercular activity H37Rv using L. J. Slope Method and anti-oxidant activity using DPPH and ABTS bioassay method.The application of microwave technology for the rapid synthesis of biologically significantthiocoumarin analogues is very promising because of its shorter reaction time and higheryield. Some of these new derivatives showed moderate to good in-vitro anti-bacterial, anti-fungal,and anti-tubercular activity. Compounds B4 and B7 appeared to have high radical scavenging efficaciesas 35.32 ± 0.446 and 33.97 ± 1.069 μg/mL ± SD of IC50 values in DPPH and ABTS bioassay,respectively.Microwave-assisted synthesis provides an implicit way to discover a promising classof molecular entities for the development of new anti-microbial and anti-oxidant agents. Oxadiazoleand pyrimidine bearing thiocoumarin derivatives showed improved anti-microbial, antitubercular,and anti-oxidant activity.
本研究目的是在微波照射下合成嘧啶- 1,3,4-恶二唑环系硫代香豆素支架,并描述其药理活性。本文报道了一种在微波辐射下高效、简单的Lewis酸催化合成嘧啶和1,3,4-恶二唑基序的新型硫代香豆素系列化合物。微波辅助技术具有收率高、工艺干净、选择性好、反应时间短、后处理简单等优点。本研究的目的是设计和合成巯基香豆素-嘧啶- 1,3,4-恶二唑环体系的微波辅助加热支架。我们的主要重点是强调为合成具有药理意义的杂环基团而开发的合成方法,并且也突出了微波加热提供的独特优势。在微波辐射下合成了巯基香豆素与嘧啶和1,3,4-恶二唑基序。所有合成的分子通过IR、1H NMR、13CNMR和质谱进行了分离。测定了合成的化合物对2种革兰氏阴性菌(大肠杆菌、铜绿假单胞菌)、2种革兰氏阳性菌(金黄色葡萄球菌、金黄色葡萄球菌)的抑菌活性。MIC (minimum inhibityconcentration)法测定3种真菌(C. albicans, A. niger, A. clavatus), L. J. Slope法测定抗结核活性H37Rv, DPPH和ABTS生物测定法测定抗氧化活性。微波技术具有反应时间短、产率高的优点,在快速合成具有重要生物学意义的硫代香豆素类似物方面具有广阔的应用前景。这些新的衍生物显示出中等到良好的体外抗菌、抗真菌和抗结核活性。化合物B4和B7具有较强的自由基清除能力,DPPH和ABTS的IC50值分别为35.32±0.446和33.97±1.069 μg/mL±SD。微波辅助合成为开发新的抗微生物和抗氧化剂提供了一种潜在的方法来发现一类有前途的分子实体。含恶二唑和嘧啶的硫代香豆素衍生物具有较好的抗微生物、抗结核和抗氧化活性。
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引用次数: 1
Microwave Radiation Effects on the Acidic Properties of Fe/ZSM-5 Catalysts for Methanol Conversion 微波辐射对Fe/ZSM-5甲醇转化催化剂酸性的影响
IF 0.8 Pub Date : 2021-02-12 DOI: 10.2174/2213335608666210212103541
T. S. Ntelane, Themba E. Tshabalala, C. M. Masuku, M. Scurrell
To use the microwave radiation as the post-treatment method to tune the acidicproperties of Fe/ZSM-5 catalyst.ZSM-5 zeolite is a widely used standard catalyst in the methanol conversion toolefins and high-octane gasoline range hydrocarbons. However, the coke deposition and the concentrationof acid sites determine its overall catalytic activity. Thus, the concentration of acid sitesmore precisely, the number of Brønsted acid sites, is vital in determining the activity of ZSM-5 zeoliteand product distribution in the methanol-to-hydrocarbons reaction.(1) To modify ZSM-5 using an iron solution to form Fe/ZSM-5 via the impregnationmethod.(2) To tune the acidic properties of Fe/ZSM-5 using microwave radiation.(3) To check and determine the concentration of acidic sites using n-propylamine temperature-programmedsurface reaction.(4) To check the effect of microwave radiation and acidic properties in the methanol conversion(product distribution) via methanol temperature-programmed surface reaction.Two sets of zeolites were used, with iron being introduced by ion-exchange from ferricnitrate (Fe(NO3)3 9H2O, Sigma Aldrich, ≥ 98% metal) solutions. These two series were designatedas Z (0.5FeZ10/0-700) and X (0.5FeX10/0-700) after microwave treatment. The Z and X series possess theSi/Al framework ratio of 30 and 80, respectively. The TPSR studies were then conducted for characterizationand catalytic tests.From the C3H9N-TPSR experiments, it was found that the concentration of Brønsted acidsites decreased with increasing microwave power level. Both X and Z series exhibited high selectivityto propene than ethene. Microwave treated catalysts (0.5FeZ10/280 and 0.5FeX10/462) with decreasedconcentration of Brønsted acid sites showed the highest propene/ethene ratios of 1.67 and5.27, respectively.From the results obtained, it was found that the amount of methane evolved (as a measureof coke deposited) and the concentration of Brønsted acid sites decreased with increasing microwavepower level (0-700 Watts). High selectivity to propene was found when using both X series(0.5FeX10/0-700) and Z series (0.5FeZ10/0-700) as catalysts. After decreasing the concentration ofBrønsted acid using microwave treatment, the highest P/E ratios were observed for 0.5FeX10/280,0.5FeX10/462, 0.5FeZ10/280 and 0.5FeZ10/462 catalysts.It is reasonable to suggest that microwave radiation could be a feasible post-synthesis modificationstep to produce ZSM-5 based catalysts that exhibit reduced concentration of Brønsted acid sites, reducedmethane formation, increased catalytic activity and selectivity.
采用微波辐射作为后处理方法,对Fe/ZSM-5催化剂的酸性进行了调整。ZSM-5沸石是甲醇转化烯烃和高辛烷值汽油系列碳氢化合物中广泛使用的标准催化剂。然而,焦炭的沉积和酸性位点的浓度决定了其整体催化活性。因此,确切地说,酸性位点的浓度,即Brønsted酸性位点的数量,对于确定ZSM-5沸石的活性和甲醇-烃反应中产物的分布至关重要。(1) 用铁溶液对ZSM-5进行改性,通过浸渍法形成Fe/ZSM-5。(2) 利用微波辐射调节Fe/ZSM-5的酸性性质。(3) 使用正丙胺温度程序化表面反应检查和测定酸性位点的浓度。(4) 通过甲醇温度程序化表面反应,检查微波辐射和酸性性质对甲醇转化(产物分布)的影响。使用两组沸石,通过离子交换从硝酸铁(Fe(NO3)3 9H2O,Sigma-Aldrich,≥98%金属)溶液中引入铁。这两个系列在微波处理后被命名为Z(0.5FeZ10/0-700)和X(0.5FeX10/0-700)。Z和X系列的Si/Al骨架比分别为30和80。然后进行了TPSR研究以进行表征和催化测试。从C3H9N-TPSR实验中发现,Brønsted酸性位点的浓度随着微波功率水平的增加而降低。X和Z系列对丙烯的选择性均高于乙烯。Brønsted酸中心浓度降低的微波处理催化剂(0.5FeZ10/280和0.5FeX10/462)显示出最高的丙烯/乙烯比,分别为1.67和5.27。从获得的结果中发现,随着微波功率水平(0-700瓦)的增加,甲烷的释放量(作为沉积焦炭的测量)和Brønsted酸位点的浓度降低。当使用X系列(0.5FeX10/0-700)和Z系列(0.5Fe Z10/0-700)作为催化剂时,发现对丙烯的高选择性。在使用微波处理降低Brønsted酸的浓度后,0.5FeX10/280、0.5FeX10/462、0.5FeZ10/280和0.5FeZ10/462催化剂的P/E比最高。有理由认为,微波辐射可能是生产ZSM-5基催化剂的一个可行的合成后改性步骤,该催化剂表现出降低的Brønsted酸位点浓度、减少的乙烷形成、提高的催化活性和选择性。
{"title":"Microwave Radiation Effects on the Acidic Properties of Fe/ZSM-5 Catalysts for Methanol Conversion","authors":"T. S. Ntelane, Themba E. Tshabalala, C. M. Masuku, M. Scurrell","doi":"10.2174/2213335608666210212103541","DOIUrl":"https://doi.org/10.2174/2213335608666210212103541","url":null,"abstract":"\u0000\u0000To use the microwave radiation as the post-treatment method to tune the acidic\u0000properties of Fe/ZSM-5 catalyst.\u0000\u0000\u0000\u0000ZSM-5 zeolite is a widely used standard catalyst in the methanol conversion to\u0000olefins and high-octane gasoline range hydrocarbons. However, the coke deposition and the concentration\u0000of acid sites determine its overall catalytic activity. Thus, the concentration of acid sites\u0000more precisely, the number of Brønsted acid sites, is vital in determining the activity of ZSM-5 zeolite\u0000and product distribution in the methanol-to-hydrocarbons reaction.\u0000\u0000\u0000\u0000(1) To modify ZSM-5 using an iron solution to form Fe/ZSM-5 via the impregnation\u0000method.\u0000\u0000(2) To tune the acidic properties of Fe/ZSM-5 using microwave radiation.\u0000\u0000(3) To check and determine the concentration of acidic sites using n-propylamine temperature-programmed\u0000surface reaction.\u0000\u0000(4) To check the effect of microwave radiation and acidic properties in the methanol conversion\u0000(product distribution) via methanol temperature-programmed surface reaction.\u0000\u0000\u0000\u0000Two sets of zeolites were used, with iron being introduced by ion-exchange from ferric\u0000nitrate (Fe(NO3)3 9H2O, Sigma Aldrich, ≥ 98% metal) solutions. These two series were designated\u0000as Z (0.5FeZ10/0-700) and X (0.5FeX10/0-700) after microwave treatment. The Z and X series possess the\u0000Si/Al framework ratio of 30 and 80, respectively. The TPSR studies were then conducted for characterization\u0000and catalytic tests.\u0000\u0000\u0000\u0000From the C3H9N-TPSR experiments, it was found that the concentration of Brønsted acid\u0000sites decreased with increasing microwave power level. Both X and Z series exhibited high selectivity\u0000to propene than ethene. Microwave treated catalysts (0.5FeZ10/280 and 0.5FeX10/462) with decreased\u0000concentration of Brønsted acid sites showed the highest propene/ethene ratios of 1.67 and\u00005.27, respectively.\u0000\u0000\u0000\u0000From the results obtained, it was found that the amount of methane evolved (as a measure\u0000of coke deposited) and the concentration of Brønsted acid sites decreased with increasing microwave\u0000power level (0-700 Watts). High selectivity to propene was found when using both X series\u0000(0.5FeX10/0-700) and Z series (0.5FeZ10/0-700) as catalysts. After decreasing the concentration of\u0000Brønsted acid using microwave treatment, the highest P/E ratios were observed for 0.5FeX10/280,\u00000.5FeX10/462, 0.5FeZ10/280 and 0.5FeZ10/462 catalysts.\u0000\u0000\u0000\u0000It is reasonable to suggest that microwave radiation could be a feasible post-synthesis modification\u0000step to produce ZSM-5 based catalysts that exhibit reduced concentration of Brønsted acid sites, reduced\u0000methane formation, increased catalytic activity and selectivity.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47198010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer 酸功能化介孔聚合物微波辅助合成3,4-二氢嘧啶-2(1H)- 1
IF 0.8 Pub Date : 2021-02-01 DOI: 10.2174/2213335608666210329130736
Bishwajit Changmai, K. Rajkumari, D. Das, Lalthazuala Rokhum
Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwaveirradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDXwere employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1),high surface area (90.44 m2g-1) and mesoporous nature of the catalyst effectively promoted thesynthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98%) as compared to conventional heating (15-25 % yield) under our optimized reaction conditionssuch as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (withrespect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesizedBiginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalystwas investigated up to 5 successive cycles and it showed great stability towards the synthesis of3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.
研究了酸官能化介孔聚合物催化剂的合成及其在微波辐射下通过Biginelli缩合反应合成3,4-二氢嘧啶-2(1H)-酮的应用。采用FT-IR、BET、TEM、SEM和EDX等分析技术对合成的聚合物催化剂进行了表征。催化剂的高酸度(1.15mmol g-1)、高表面积(90.44m2g-1)和介孔性质有效地促进了3,4-二氢嘧啶-2(1H)-酮的合成。在醛/乙酰乙酸乙酯/尿素摩尔比为1:1:1.2、催化剂负载量为6wt.%(相对于醛)、温度为80°C、微波功率为50W的优化反应条件下,微波辐射显示出比常规加热(15-25%产率)更高的产率(89-98%)。对催化剂的可重复使用性进行了长达5个连续循环的研究,它在合成3,4-二氢嘧啶-2(1H)-酮方面表现出极大的稳定性,而产率没有任何显著下降。
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引用次数: 0
Microwave-assisted Claisen Rearrangement of 1-Allyloxy-4-hydroxybenzene in the Presence of Metal Salt 金属盐存在下1-烯丙氧基-4-羟基苯的微波辅助Claisen重排
IF 0.8 Pub Date : 2021-01-06 DOI: 10.2174/2213335607666210106094449
Fumiyoshi Ozaki, Y. Okada
Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl groupwas conducted in the presence of metal salts. The rearrangement was promoted in the presence ofan alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, whichcan efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the etherealoxygen, and this structure could also absorb microwaves efficiently.
在金属盐的存在下进行了烯丙氧基苯与羟基的微波辅助Claisen重排。碱金属盐的存在促进了重排,因为反应底物转化为能有效吸收微波的苯氧离子。相比之下,路易斯酸与以太氧具有强配位性,并且这种结构也可以有效地吸收微波。
{"title":"Microwave-assisted Claisen Rearrangement of 1-Allyloxy-4-hydroxybenzene in the Presence of Metal Salt","authors":"Fumiyoshi Ozaki, Y. Okada","doi":"10.2174/2213335607666210106094449","DOIUrl":"https://doi.org/10.2174/2213335607666210106094449","url":null,"abstract":"\u0000\u0000Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl group\u0000was conducted in the presence of metal salts. The rearrangement was promoted in the presence of\u0000an alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, which\u0000can efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the ethereal\u0000oxygen, and this structure could also absorb microwaves efficiently.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48616658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
期刊
Current Microwave Chemistry
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