Facile Microwave‐assisted Synthesis of 1,3,5‐Trisubstituted Pyrazoline Derivatives Incorporating Sulfonyl Moiety

We developed an environmentally benign, convenient microwave‐assisted process for the construction of 1,3,5‐trisubstitued pyrazolines ( 10a ～ 10f , 11a ～ 11f , 12a ～ 12f , 13a ～ 13f ). Chalcones, as the key intermedi‐ ates, were obtained by the condensation of each of appropriately substituted aromatic aldehydes ( 1 ～ 4 ) with 4‐substituted acetophenones ( 5a ～ 5f ) via a Claisen‐Schmidt reaction under the action of microwave irradiation. Cyclization of the chalcones ( 6a ～ 6f , 7a ～ 7f , 8a ～ 8f , 9a ～ 9f ) with p‐toluene sulfonhydrazide af‐ forded 1,3,5‐trisubstitued pyrazoline derivatives using microwave‐assisted process in 25 min and 140 watt power in glycol. The structures of targeted compounds were established by IR, ¹H NMR, MS and ele‐ mental analysis. The results indicate that microwave‐assisted synthetic process presents advantages in terms of enhancement in rate, decrease in reaction time, clean reaction and convenient operation.     

Synthesis and Antimicrobial of Some Novel-5-carbomethoxy-2-pyridone Derivatives Containing Sulfonamide Moiety

Dimethyl 4-(methoxymethylene)-2-pentenedioate 2 was selected as the starting material for the synthesis of some novel 2-pyridones containing sulfonamide moiety, which we expected to have biological activities such as bactericidal and fungicidal or other applications of certain interest.     

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-Assisted Synthesis of 2-Long Alkenyl Chain Benzoxazoles and Naphtho[2,3-d]oxazoles and Their Antimicrobial Evaluation

A microwave-assisted combinatorial synthesis of 2-long alkenyl chain benzoxazoles and naphtho[2,3-d]oxazoles with a catalytic amount of phosphorus pentasulphide at ambient pressure has been developed. This procedure constitutes a simple, practical, and green synthetic method for benzoxazoles and their structural analogs. All the compounds [2(a–d) through 6(a–d)] have been screened for antibacterial and antifungal activity. The compounds have showed good activity against Gram-positive and Gram-negative bacteria. All the compounds have also showed good results against almost all fungal strains. The structures of the synthesized compounds are elucidated by IR, ¹H NMR, ¹³C NMR, MS data, and elemental analysis.     

Design,Synthesis, and Antimicrobial Evaluation of Novel Thienopyrimidines and Triazolothienopyrimidines

2-Cyanoacetohydrazide and 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene derivatives were exploited as starting materials for the syntheses of novel thienopyrimidines and triazolothienopyrimidines. The proclivity of these compounds toward one-carbon donor reagents such as carbon disulfide, phenyl isothiocyanate, and aromatic aldehydes was investigated. The structures of all synthesized compounds were ascertained by spectral and analytical data. The antimicrobial activity of the target synthesized compounds was tested against various microorganisms.     

Microwave-assisted Catalyzed Synthesis and In vitro Bioactivity Evaluation of Benzimidazoles Bearing Phenolic Hydroxyl

An efficient and facile method was introduced for the synthesis of benzimidazoles in this paper. The optimum reaction conditions were determined. A series of benzimidazoles bearing phenolic hydroxyl(2a-2t) were synthesized in moderate to excellent yields starting from differently substituted hydroxyl benzaldehyde and 4-position substituted o-phenylenediamine via nucleophilic addition in the presence of catalyst Na₂S₂O₅ under microwave irradiation condition. Herein, effects of the catalyst, molar ratio of reactants, reaction temperature and solvent were investigated. The optimal reaction condition was determined. The effect of DMF and EtOH solvent on the reaction was compared. The synthesized compounds were characterized by FTIR, HRMS, ¹H NMR and ¹³C NMR spectroscopy. Further, the bacteriostatic activities of the synthesized compounds were evaluated with ciprofloxacin and itraconazole as a positive control, respectively. Compounds 2b, 2n, 2q and 2r exhi-bited some antibacterial activity. The lowest MIC of antibacterial activity of compound 2b was 32 μg/mL. Meanwhile, the luminescence property of compound 2b was studied. The antibacterial activity of compound 2b, along with their good fluorescence performance highlighted the potential of these compounds as lead structures and owned fluorescence trace for further study towards the development of novel drugs and functional mechanisms in living organisms.     

Microwave promoted synthesis and antimicrobial activity of 3-thiazole substituted 2-styryl-4(3H)-quinazolinone derivatives

The present paper describes an optimized reaction condition for the microwave promoted synthesis of newer 3-thiazole substituted 2-styryl-4(3H)-quinazolinone derivatives, which in turn were prepared in good yield by the treatment of various 2-styryl benzoxazinone derivatives with various 2-aminothiazoles using co-solvent under microwave irradiation. All the compounds were characterized by various spectroscopic techniques and analytical methods. All newly synthesized compounds have been screened for their in vitro antibacterial and antifungal activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus megaterium,Bacillus subtilis, and Aspergillus niger.     

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。     

1-苯基-3-(3'-吲哚基)-5-取代苯基-2-吡唑啉的合成及1H NMR和MS中的取代基效应

J-(3'-吲哚基)-3-取代苯基-2-丙烯-1-酮与茉肼反应,合成了10种新的1-苯基-3-(3'-吲哚基)-5-取代苯基-2-吡唑啉衍生物,其结构通过各种波谱证实.讨论了此系列化合物¹HNMR和Ms中的取代基效应,得出取代基常数σ或σ⁺与质子化学位移,碎片相对丰度之间存在着良好的线性关系.     

新型含巴比妥酸的芳香酰腙类化合物的合成、晶体结构及抑菌活性

在微波辅助下,1,3-二甲基-5-醛基巴比妥酸与芳氧基/芳胺基乙酰肼及含氮杂环乙酰肼缩合制备新型酰腙化合物,并对其抑菌活性进行评价的研究。 新化合物的结构经过元素分析、红外光谱、核磁共振谱、质谱和X射线单晶衍射等技术手段确认。 体外的抑菌活性实验显示,部分目标化合物呈现出优于环丙沙星的抑菌活性。 经过构效关系分析表明,当芳基为含氮杂环时,所形成的化合物抗菌活性与芳基为苯环时相比明显较强,抑菌活性最强的酰腙化合物2t对金黄色葡萄球菌的最小抑菌浓度(MIC)值为0.8 g/L,对大肠杆菌的最小抑菌浓度(MIC)值为1.6 g/L。     

Synthesis and Characterization of Chloralose-Derived Thiosemicarbazones and Semicarbazones and Investigation of Their Antimicrobial Properties

Thiosemicarbazones(7–10)/semicarbazones(11–14) were synthesized in good yields via the condensation of α-gluco-, β-gluco-, galacto-, manno- chloralose derived 1,4-furanodialdoses (1-4) with thiosemicarbazide(5)/semicarbazide(6). The structures of all products were characterized by FTIR, NMR spectroscopic methods and elemental analysis. The compounds have been found to display moderate antimicrobial activity against Gram-positive, Gram-negative bacteria and antifungal activity against a Candida albicans. MIC values of the compounds range from 260 to 1510 μg/mL.     

Ecofriendly Solventless Synthesis and Reduction Reaction of Some Triazole Compounds and Evaluation of Their Antimicrobial Activity

A number of triazole-3-one compounds have been synthesized, and reduction of the carbonyl group in the molecule has been carried out to give a corresponding hydroxyl group that possesses asymmetric carbon atom in good yields and short reaction times. It is ecofriendly because it is produced by straightforward microwave irradiation in the absence of solvent. All newly synthesized compounds were also screened for their antimicrobial activities. The antimicrobial activity study revealed that 2d, 2i, 3c, and 3g–j showed good activity against a variety of microorganisms.

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

Synthesis and Antimicrobial Evaluation of Some New 1,5-Benzothiazepine Derivatives and Their Ribofuranosides

( - )- cis -2(4-Methoxyphenyl)-3-hydroxy/methoxy-6,8-dichloro/6-chloro-2,3-dihydro-1,5-benzothiazepin-4[5H/5-chloroacetyl/5-(4'-methylpiperazino-1')acetyl]-ones have been synthesized by the condensation of 2-amino-3,5-dichloro/3-chloro benzenethiol with methyl-( - )- trans -3(4-methoxyphenyl)glycidate in xylene. Ribofuranosides viz ( - )- cis -2(4-methoxyphenyl)-3-methoxy-6,8-dichloro/6-chloro-2,3-dihydro-1,5-benzothiazepine-4-[5-(2',3',5'-tri- O -benzoyl- g -D-ribofuranosyl)-ones have been synthesized by the treatment of 3-methoxy derivatives of 1,5-benzothiazepines with sugar viz g -D-ribofuranose-1-acetate-2,3,5-tribenzoate in toluene at vacuo. Synthesized compounds have been characterized by elemental analysis, IR, 1 H NMR spectral studies and screened for their antimicrobial activity.     

Synthesis, Characterization, and Evaluation of Antimicrobial Activity of Some 1,2,4-Triazole Derivatives Bearing an Antipyryl Moiety

Summary.  Some novel 4-[[2-[[5-(2-furanyl)-4-alkyl/aryl-4H-1,2,4-triazol-3-yl]thio]-acetyl/propionyl]-amino]-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazoles were synthesized and evaluated for in vitro antibacterial activity against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, and Enterococcus faecalis ATCC 29212 and antifungal activity against Candida albicans ATCC 10231, Candida parapsilosis ATCC 22019, Candida krusei ATCC 6258, Candida parapsilosis, Trichophyton mentagrophytes var. erinacei NCPF 375, Microsporum gypseum NCPF 580, and Trichophyton rubrum using the microbroth dilution method. All of the compounds were found to be ineffective against the above bacteria within the applied MIC ranges. On the other hand, they were effective against fungi to different degrees. Three compounds showed high activity against C. parapsilosis and T. mentagrophytes var. erinacei NCPF 375 (MIC = 8 μg cm⁻³). The in vitro antimycobacterial activity of the new compounds was also investigated against Mycobacterium tuberculosis H₃₇RV (ATCC 27294) in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA). Compounds exhibiting fluorescence were tested in the BACTEC 460 radiometric system. The most active compound was found with 66% inhibition at >6.25 μg cm⁻³. Corresponding author. E-mail: nurayulusoy@yahoo.com Received July 24, 2002; accepted August 26, 2002     

Synthetic Utility of Enaminonitrile Moiety in Heterocyclic Synthesis: Synthesis of Some New Thienopyrimidines

The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile ( 4 ) was condensed with p-anisaldehyde affording the Schiff base ( 5 ). Acylation of the thienopyridine derivative ( 4 ) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives ( 6 ) and ( 7 ). Condensation of ( 4 ) with triethylorthoformate yielded the ethoxymethyleneamino derivative ( 8 ), which was treated with hydrazine hydrate to give the hydrazide derivative ( 9 ), which in turn was converted to a triazolopyrimidine derivative ( 10 ) upon treatment with freshly distilled acetic anhydride. Thiation of ( 4 ) with carbon disulfide afforded the pyrimidine dithione derivative ( 11 ), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative ( 12 ).On the other hand, treatment of ( 4 ) with formamide yielded the aminopyrimidine derivative ( 13 ), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1 4 ). Chlorination of (1 4 ) with a mixture of phosphorus pentachloride and phosphorus oxychloride gave the chloropyrimidine derivative ( 15 ), which in turn afforded the hydrazide derivative ( 9 ) upon treatment with hydrazine hydrate. Hydrazinolysis of ethyl-3-amino-5-bromo-4,6-dimethylthieno[2,3-b]pyridine-2-carboxylate ( 17 ) gave the hydrazino derivative ( 18 ), which in turn was converted to 8-bromo-7,9-dimethyl-3-formylaminopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 19 ) and 8-bromo-3-diacetylamino-2,7,9-trimethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 20 ) upon treatment with formic acid and freshly distilled acetic anhydride, respectively.     

Synthesis and Antimicrobial Activity of New Tetrazoles Incorporating Isoindole‐1,3‐dione Moiety and Their Sugar Derivatives

New tetrazole derivatives linked to isoindole‐1,3‐dione were prepared starting from the corresponding nitrile derivatives. The substituted hydrazides, their corresponding sugar hydrazones, and the derived acyclic C‐nucleoside analogs were also synthesized. The antimicrobial results indicated that most of the tested compounds exhibited moderate to high activity, whereas few compounds were found to exhibit little or no activity against the tested microorganisms.     

ChCl: Gly (DESs) Promote Environmentally Benign Synthesis of Xanthene Derivatives and Their Antitubercular Activity

A ChCl: Gly (DESs) promoted environmentally benign method was developed for the first time using the reaction of aryl aldehydes and dimedone to give excellent yields of xanthene analogues. The major application of this present protocol is the use of green solvent, a wide range of substrate, short reaction times, ease of recovery, the recyclability of the catalyst, high reaction yield, and ChCl: Gly as an alternative catalyst and solvent. In addition to this, all the synthesized compounds were evaluated for their in vitro antimycobacterial activity against M. tuberculosis H37Ra (MTB) and M. bovis BCG strains. The compounds 3d, 3e, 3f, and 3j showed significant antitubercular activity against MTB and M. bovis strains with minimum inhibitory concentration (MIC) values of 2.5−15.10 µg/mL and 0.26–14.92 µg/mL, respectively. The compounds 3e, 3f, and 3j were found to be nontoxic against MCF-7, A549, HCT 116, and THP-1 cell lines. All the prepared compounds were confirmed by ¹H NMR and ¹³C NMR analysis.     

Preparation and Spectral and Biological Investigation of vic-Dioxime Ligands Containing Piperazine Moiety and Their Mononuclear Transition-Metal Complexes

Two vic-dioxime ligands, N-(4-benzylpiperazine-1-yl) p-tolylglyoxime (L¹H₂) and N,N′-bis(4-benzylpiperazine-1-yl) glyoxime (L²H₂), containing piperazine moieties were synthesized, and their Ni(II), Cu(II), Co(II) and Zn(II) complexes were obtained. The ligands were characterized by elemental analysis, Fourier transform–infrared (FT-IR), ultraviolet–visible NMR (¹H, ¹³C, and heteronuclear multiple-bond correlation), and electrospray ionization (ESI) mass spectrometry. The isolated complexes were characterized by a combination of elemental analysis, IR, UV-vis, and ESI mass spectrometry and in the case of Ni(II) and Zn(II) complexes by ¹H and ¹³C NMR spectroscopy. The electrochemical behaviors of the ligands and their complexes were studied by cyclic voltammetry (CV) in dimethylsulfoxide solution containing tetrabutylammoniumtetrafluoroborate (TBATFB). The antibacterial activity was also studied against S. aureus ATCC 25923, S. aureus ATCC 29213, S. mutans RSHM 676, E. faecalis ATCC 29212, E. coli ATCC 25922, and P. aeruginosa ATCC 27853. The antimicrobial test results indicated that all the compounds have good antibacterial activity against P. auriginosa ATCC 27853 bacteria and were as effective as ampicilin.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Environmentally Sustainable and Chemo‐selectively Favorable Synthesis of Substituted 2H‐Pyran‐2‐ones in Water under MWI

In this paper, a novel synthesis of diversely substituted 2H‐pyran‐2‐ones via the tandem reaction of 3‐hydroxyhexa‐4,5‐allenic esters in water under the promotion of MWI has been developed. Compared with those reactions carried out in organic solvents, water mediated synthesis of poly‐substituted 2H‐pyran‐2‐ones is not only environmentally sustainable, but also chemo‐selectively favorable.