Design,Ultrasonic-assisted Synthesis and Evaluation In vitro Antimicrobial Activity of Bis-isoxazole Derivatives Bearing Chloro-pyridinyl Group

An ultrasonic-assisted synthesis of bis-isoxazole derivatives was developed. Eight 3-(6-chloropyridin-3-yl)-5-{[(3-aryli-soxazol-5-yl)methoxy]methyl}isoxazoles were synthesized by 1,3-dipolar cycloaddition reaction between substituted isoxazolyl alkyne compounds and 6-chloro-N-hydroxynicotinimidoyl chloride. The structures of the synthesized compounds were confirmed by HRMS, FTIR, ¹H and ¹³C NMR spectroscopy. Wherein, the antifungal and antibacterial activities of target compounds were tested. The synthesized compounds 6a and 6h exhibited better antifungal activity in comparison with the standard drug itraconazole. The minimum inhibitory concentrations(MICs) of both compound 6a and compound 6h were both 4 μg/mL against Candida albicans ATCC 10231.     

芳香基苯并咪唑衍生物的合成、表征及抑菌活性研究

在微波辐射下,通过二茂铁磺酰氯和相应的苯并咪唑合成了4种芳香基苯并咪唑衍生物。经^1H NMR、MS及元素分析确证产物结构。通过X线衍射测定了化合物4a的晶体结构。用琼脂稀释法测定化合物抑菌活性,并与对照药剂50%多菌灵可湿性粉剂比较,结果表明化合物4a～4d对番茄早疫病菌、烟草赤星病菌和小麦赤霉病菌有与对照药剂近似的抑菌活性。     

Environmentally Benign Synthesis of 2-Pyrazolines and Cyclohexenones Incorporating Naphthalene Moiety and Their Antimicrobial Evaluation

We reported the environmental benign synthesis of chalcones,2-pyrazolines and cyclohexanones under microwave irradiation.Chalcones were obtained by the condensation of each of 2-hydroxyacetophenone derivatives with a-naphthaldehyde under microwave irradiation.The condensation reactions of each of synthesized chalcones with phenyl hydrazine under microwave irradiation in the presence of dry acetic acid as a cyclizing agent gave 2-pyrazolines.Also,the new cyclohexenone derivatives,valuable intermediates to synthesize fused heterocycles,have been prepared by the cyclocondensation of each of hydroxychalcones with ethyl acetoacetate.The structures of the synthesized compounds were elucidated by infrared（IR） spectrometry,nuclear magnetic resonance（NMR）,mass spectrometry（MS） and elmental analysis.The results indicate that unlike classical heating,microwave irradiation results in higher yields with shorter and cleaner reactions.The synthesized compounds were screened for antimicrobial activity against Staphylococcus aureus,Escherichia coli,Candida Albicans and Aspergillus niger.We clarified the effects of different substituents in the tested compounds on the obtaind antibacterial activities and antifungal activities.     

Synthesis of 1H‐Imidazoles Catalyzed by Cu‐Nanoparticle and Its Physicochemical Properties

Series of 1‐arylmethyl‐4, 5‐dihydro‐2‐aryl‐1H‐imidazole were synthesized expeditiously in good yields from 1,2‐diaminoethane and aromatic aldehydes in the presence of Cu nanoparticle under microwave irradiation in solvent‐free method. Monodisperse spherical Cu nanoparticles with a diameter range of 45 ± 8 nm were synthesized by polyol process. The particle size and elemental structure of copper nanoparticles were confirmed by XRD data and was found to be having a face‐centered cubic structure. The resulting substituted imidazoles have been studied in the achievement of degree of drug absorption enhancement as well as the potential associated toxicity on the basis of hypothetical antibacterial pharmacophores and structures that were designed to interact with both of gram‐positive and gram‐negative bacteria. All the synthesized molecules were characterized on the basis of 1H NMR, 13C NMR, mass spectrometry, and elemental data.     

微波辐照合成羟基功能化离子液体氯盐中间体

采用微波辐照法合成了4种羟基功能化离子液体中间体氯化1-甲基-3-羟乙基咪唑、氯化N-羟乙基吡啶、氯化1-甲基-3-(2,3-二羟基)丙基咪唑和氯化N-(2,3-二羟基)丙基吡啶,考察了微波功率、辐射方式和辐射时间对反应产率的影响。结果表明,利用常规加热方法合成这4种离子液体中间体耗时长达24～96h,而用微波方法只需110～390s,反应时间大大缩短,同时微波方法较常规加热方法产率也略有提高。     

Microwave-assisted fast and efficient synthesis of some crown ethers

13-Crown-4,16-crown-5,dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields.Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect.     

硝基苯并咪唑衍生物的合成、表征及抑茵活性的测定

以苯并咪唑为原料，经硝化、二茂铁磺酰化等步骤，合成了8种未见文献报道的硝基苯并咪唑衍生物，其结构经MS，^1H NMR和元素分析确证．由于硝基苯并咪唑的互变异构，二茂铁磺酰化后，产生两个异构体，用X射线衍射仪测定了化合物2a的晶体结构．初步的抑菌实验结果表明，该系列化合物具有良好的抑菌作用，其抑菌活性均优于对照药剂50％多菌灵可湿性粉剂．     

硝基苯并咪唑衍生物的合成、表征及抑菌活性的测定

以苯并咪唑为原料,经硝化、二茂铁磺酰化等步骤,合成了8种未见文献报道的硝基苯并咪唑衍生物,其结构经MS,¹H NMR和元素分析确证.由于硝基苯并咪唑的互变异构,二茂铁磺酰化后,产生两个异构体,用X射线衍射仪测定了化合物2a的晶体结构.初步的抑菌实验结果表明,该系列化合物具有良好的抑菌作用,其抑菌活性均优于对照药剂50%多菌灵可湿性粉剂.     

Synthesis of Guanylhydrazones Under Microwave Irradiation

Abstract

The reaction of aromatic aldehydes and ketones with aminoguanidine hydrochloride under microwave irradiation (MWI) afforded guanylhydrazones in shorter reaction times and improved yield as compared to the conventional methodology.     

离子液体与微波协同促进有机合成反应

介绍了离子液体作溶剂、助溶剂、催化剂和反应试剂与微波协同促进有机合成的研究进展。离子液体与微波协同促进有机合成反应,缩短了反应时间,提高了反应的选择性和产率,对环境更加友好。     

微波辅助合成5-亚甲基-2,3-二苯基-4-噻唑酮类衍生物

本文报道了一种通过微波辅助合成5-亚甲基-2,3-二苯基-4-噻唑酮类衍生物的新型方法。在以K2CO3 为碱、H2O 为溶剂、四丁基溴化铵（TBAB）为催化剂的条件下,2,3-二苯基-4-噻唑酮与取代醛在微波辅助下发生Knoevenagel 反应,生成5-亚甲基-2,3-二苯基-4-噻唑酮类衍生物,产率最高可达85%。     

Synthesis and crystal morphology control of AlPO4-5 molecular sieves by microwave irradiation

AlPO₄-5 molecular sieves have been synthesized by the hydrothermal and solvothermal reactions using triethylamine as a template, aluminum isopropoxide and orthophosphate as the aluminum and phosphorus resource under microwave irradiation. The influences of various experimental parameters, such as reaction time, reaction temperature and reaction power, have been systematically investigated. The morphology control of AlPO₄-5 molecular sieves was achieved by changing the dosage of solvent and HF to control the solvent polarity and control the nucleation respectively. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and so on. The results show that the aspect ratio of the AlPO₄-5 molecular sieves increases with the increase of the solvent polarity and with the increasing concentration of HF, the morphology of AlPO₄-5 molecular sieves changes from hexagonal plate to hexagonal rod.     

Synthesis and Anticoagulant Bioactivity Evaluation of 1, 2, 5-Trisubstituted Benzimidazole Fluorinated Derivatives

Some 1,2,5-trisubstituted benzimidazole fluorinated derivatives were designed and screened by molecular docking. Five compounds which obtained high scores were selected to synthesize. All the target products were char-acterized by ¹H NMR, ¹³C NMR and high resolution mass spectra(HRMS) and preliminarily screened for inhibitory activity against thrombin, among which three compounds(5a, 5c and 5e) were evaluated in vitro. The results showed that compounds 5a, 5c and 5e exhibited better anticoagulant activity than argatroban. Docking simulations demonstrated that these compounds may act as candidates for further studies on thrombin inhibitors.     

Zeolites. Efficient and Eco-friendly Catalysts for the Synthesis of Benzimidazoles

Summary. A superior method of synthesis of 2-substituted benzimidazoles by means of the heterogeneous catalysis of synthetic and natural zeolites in the reaction of 1,2-diaminobenzene with acid chlorides is described.     

微波辐射固体酸催化合成马来酸双酯

首次在微波辐射下，用活性炭固载对甲苯磺酸催化合成了马来酸双酯．当微波辐射功率为150W．正辛醇：酸酐＝3：1，催化剂用量为2．5g时，反应20min后，马来酸酐转化率达89．8％，产物的选择性为99．5％．同时，也发现随着醇的炭数增多，反应温度和反应速率增加；在微波辐射条件下，酯化反应速率、产物选择性都高于常规加热方式下的反应结果．     

Synthesis and Bioactivity Evaluation of Novel N-Pyridylpyrazolemethanamine Derivatives

To further explore the structure-activity relationship(SAR) of amide bridge moeity of anthranilic diamides derivatives, a series of N-pyridylpyrazole derivatives was designed, synthesized and their biological activities were evaluated. The chemical structures of novel target compounds were confirmed by ¹H nuclear magnetic resonance (NMR), ¹³C NMR and elemental analyses(EA). Bioassay results of insecticidal activity demonstrated that the target compound 6h displayed 70% lethality rate against oriental armyworms at 200 mg/L. Moreover, most compounds displayed moderate to excellent antifungicidal activities against Fusarium oxysporum f. sp. cucumerinum, Cercospora arachidicola Hori, Botryosphaeria dothidea, Alternaria solani, Gibberella zeae and Phytophthora capsici at 50 mg/L. In particular, compound 6e showed 61.5% and 92.3% inhibition rate against Cercospora arachidicola Hori and Botryosphaeria dothidea, which was superior to the commercial positive control Chlorothalonil. These results will provide a potential clue for exploring novel high-effective agrochemicals.     

A Facile Synthesis of New 4,6‐Dichloropyridine Derivatives,Their Biological Evaluation for Antimicrobial and Antioxidant Activity,and Docking Studies

A facile synthesis of new 4,6‐dichloropyridine derivatives 5 ( a–f ), 6 ( a–c ), and 7 ( a–c ) were synthesized using both conventional heating and solvent‐free microwave irradiation techniques. The results revealed that the latter method is superior to the conventional heating method. The easy work‐up of the products, rapid reaction, and mild conditions are noticeable features of this protocol. Structural elucidation of the synthesized compounds was made on the basis of various spectroscopic methods. The synthesized compounds were evaluated for their in vitro antimicrobial activity (minimum inhibitory concentration; MIC) against various microbial strains using the agar well‐diffusion method. Among the compounds, 5c showed best antimicrobial activity against most of the employed strains, especially against Staphylococcus aureus, Escherichia coli, Rhizopus arrhizus, and Candida albicans. Compounds 5a , 6a , 6c , 7a , and 7c showed significant antioxidant activity when compared to the other compounds. In addition to this, theoretical docking studies were performed for the highly potent compounds 5a , 6a , 6c , 7a , and 7c against three different drug targets belonging to the oxidoreductase family, and the results were found to be highly satisfactory.     

Microwave synthesis,characterization and antimicrobial study of new pyrazolyl-oxopropyl-quinazolin-4(3H)-one derivatives

Heterocyclic compounds containing pyrazolyl-oxopropyl-quinazolin-4(3H)-one are reported to possess significant biological activity. Syntheses of 6-bromo-2-(3-chloro-2-oxopropyl)-3-(4-fluorophenyl)quinazolin-4(3H)-one 2 6-bromo-3-(4-fluorophenyl)-2-(3-hydrazinyl-2-oxopropyl)quinazolin-4(3H)-one 3 and 6-bromo-2-(3-(3-(4-(1-(2-chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-ylideneamino)phenyl)-5-(substituted phenyl)-4,5-dihydro-1H-pyrazol-1-yl)-2-oxopropyl)-3-(4-fluorophenyl)quinazolin-4(3H)-one 5a–j using microwave irradiation have been described. These compounds have been characterized on the basis of the UV, IR, ¹H NMR, ¹³C NMR, Mass and elemental analysis. Compounds have been evaluated for their antimicrobial activity.     

微波辅助合成菲并咪唑衍生物及微波非热效应

以1,10-邻菲啰啉5,6-二酮及苯甲醛(或取代苯甲醛)为原料, 在微波辐射条件下制备了一系列菲并咪唑类衍生物, 考察了温度、 时间以及投料比对微波辅助合成菲并咪唑类衍生物的影响, 并进一步探讨了微波非热效应的影响. 设计正交实验优化了反应条件; 使用SiC管作为反应容器屏蔽微波对反应的影响; 通过元素分析、 核磁共振波谱、 质谱及红外光谱等对化合物进行了表征. 结果表明, 微波辅助反应的最佳反应条件为: 1,10-邻菲啰啉-5,6-二酮与苯甲醛(或取代苯甲醛)的投料比为1: 1.5, 反应温度为100℃, 反应时间为20 min; 并且发现SiC管中反应的产率明显低于石英管反应容器. 与传统制备方法相比, 微波辅助合成方法可在更短时间内快速方便地制得菲并咪唑类衍生物; 反应温度、 反应时间以及投料比对微波辅助合成反应有明显影响; 微波非热效应有助于提高反应产率.