Synthesis and antimicrobial activities of some novel substituted 2-imidazolyl-N-(4-oxo-quinazolin-3(4H)-yl)-acetamides

Several substituted-quinazolin-3(4H)-ones 8-11ad were synthesized by condensation of 2-chloro-N-(4-oxo-substituted-quinazolin-3(4H)-yl)-acetamides with various substituted imidazoles through one pot reaction. Elemental analysis, IR, (1)H-NMR and mass spectral data confirmed the structure of the newly synthesized compounds. Synthesized quinazolin-4-one derivatives were investigated for their antitubercular, antibacterial and antifungal activities. Some of the tested compounds showed good antitubercular activity. None of the synthesized compounds showed significant antibacterial and antifungal activity.     

Synthesis, characterization, and antimicrobial evaluation of oxadiazole congeners

A series of 1,3-oxazole, 1,3-thiazole, isomeric 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,3,4-tetrazole heterocycles was synthesized. All the compounds shared as a common feature the presence of a 4-hydroxyphenyl substituent. The structures of the synthesized compounds were confirmed by MS, 1H-NMR, and elemental analysis. In vitro antimicrobial activity for all the newly synthesized compounds at concentrations of 200-25 μg/mL was evaluated against Gram+ve organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Gram-ve organisms such as Escherichia coli (E. coli), and the fungal strain Aspergillus niger (A. niger) by the cup plate method. Ofloxacin and ketoconazole (10 μg/mL) were used as reference standards for antibacterial and antifungal activity, respectively. Compounds 15, 16, and 20 showed notable antibacterial and antifungal activities at higher concentrations (200 μg/mL), whereas 17-19 were found to display significant antibacterial or antifungal activity (25-50 μg/mL) against the Gram+ve, Gram-ve bacteria, or fungal cells used in the present study.     

Synthesis of some novel thiocyanotopurine derivatives and investigation of their antimicrobial activity and DNA interactions

A series of 6-thiocyanatopurine derivatives introduced with different alkyl groups in position 9 was synthesized. The structures of the synthesized compounds were evaluated via spectroscopic methods and elemental methods of analyses. All the synthesized compounds were screened for their antibacterial activities against Gram-positive and Gram-negative bacteria and for their antifungal activities against yeast strains. All the synthesized compounds showed better antibacterial activities against Gram-positive bacteria compared to Gram-negative bacteria. DNA interactions with pBR322 DNA were determined. Most of the compounds caused conformational changes in DNA.     

Design,synthesis and biological evaluation of novel N1,N8-bis(((4-((5-aryl-1,3,4-oxadiazol-2-yl)methoxy)phenyl)amino)oxy)-1-naphthamide derivatives

A new series of 1,8-bis(4-((5-phenyl-1,3,4-oxadiazol-2-yl) methoxy)-substituted aryl) naphthalene-1,8-dicarboxamide derivatives (6a–j) were synthesized in the presence of POCl₃ and obtained good yields. All the synthesized novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, HRMS spectroscopic data and elemental analysis. All the synthesized compounds evaluated for their antibacterial and antifungal activities. The antibacterial activity screened against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli and used standard reference drug ciprofloxacin. The antifungal activity screened against two pathogenic fungal strains Aspergillus niger and Candida albicans used a reference standard drug Voriconazole. All these compounds (6a–j) demonstrate good antibacterial and antifungal activity. Among them, compounds 6h and 6c show highest antibacterial and antifungal activity.     

The synthesis and biological evaluation of a series of novel 2-COOC_2H_5/COONa substituted 1,5-benzothiazepine derivatives as antimicrobial agents

A series of novel 1,5-benzothiazepine derivatives containing COOC2H5/COONa groups at the C(2)-position were synthesized and evaluated for their antifungal and antibacterial activities by both disc diffusion and minimal inhibition concentration (MIC) methods. Most of the compounds have been shown to have moderate to good antibacterial activity against S. aureus, S. epidermidis and excellent antifungal activity against C. albicans.     

Synthesis, characterization, antibacterial and antifungal evaluation of novel monosaccharide esters

A novel series of 3-(2-furyl)acrylate monosaccharide esters Ia–f and menthyloxycarbonyl monosaccharide esters IIa–f were designed and synthesized. The chemical structures of the target compounds were confirmed by IR, 1H- and 13C-NMR and ESI-MS, and the target compounds were investigated for their in vitro antibacterial and antifungal activities. The antibacterial screening results showed that the 3-(2-furyl)acrylate monosaccharide ester derivatives Ia–f were either inactive or only weakly active against the three Gram-positive bacterial strains tested, whereas the menthyloxycarbonyl monosaccharide ester derivatives IIa–f exhibited higher levels of activity, with compound IIe being especially potent. The results of the antifungal screening revealed that compounds Ib, Ie, IIb and IIc displayed potent in vitro activities, whereas If and IIf showed promising activities against all of the microorganisms tested, with If exhibiting levels of activity deserving of further investigation.     

Synthesis and biological activities of novel ethers of quinolinone linked with coumarins

Abstract  

A series of new ethers of quinolinone linked with different substituted coumarins and benzofurans were synthesized from 4-(bromomethyl)quinolinones. All newly synthesized compounds were screened for their in vitro antibacterial and antifungal activities. Most of the compounds with chloro substitution at the C-6 or C-7 position in quinolinone showed potent antibacterial and antifungal activities. In pharmacological evaluations, some of these chloroquinolinones also showed 70–77% inhibition of inflammation after 8 h, whereas the other compounds showed 51–55% inhibition. Most of the compounds showed potent analgesic activity compared to the standard and control. The structures of all newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and EI-MS.     

Synthesis, antibacterial and antifungal activity of some derivatives of 2-phenyl-chromen-4-one

Some derivatives of 2-phenyl-chromen-4-one (flavone ring) have been synthesized and tested for antibacterial and antifungal activities along with their chalcone precursors against four human pathogenic bacteria and five plant mould fungi. The structures of the synthesized compounds were elucidated by UV, IR and¹H NMR spectroscopic techniques, and elemental analysis. The antibacterial and antifungal screens of the synthesized compounds were performed in vitro by the filter paper disc diffusion method and the poisoned food technique.     

二苯基哌嗪磺胺化合物的合成及其抗微生物活性

以乙酰苯胺和4-氯二苯甲酮为起始原料,经多步反应方便而有效地合成了二苯基哌嗪磺胺化合物,所得目标化合物及其中间体的结构经1H NMR、13C NMR、IR、MS谱和元素分析等证实.研究了化合物的体外抗微生物活性,结果表明目标化合物14和16对所测菌株的抗菌活性均优于磺胺.     

Synthesis and biological activity of new 1,3-dioxolanes as potential antibacterial and antifungal compounds

A series of new enantiomerically pure and racemic 1,3-dioxolanes 1-8 was synthesized in good yields and short reaction times by the reaction of salicylaldehyde with commercially available diols using a catalytic amount of Mont K10. Elemental analysis and spectroscopic characterization established the structure of all the newly synthesized compounds. These compounds were tested for their possible antibacterial and antifungal activity. Biological screening showed that all the tested compounds, except 1, show excellent antifungal activity against C. albicans, while most of the compounds have also shown significant antibacterial activity against S. aureus, S. epidermidis, E. faecalis and P. aeruginosa.     

Synthesis of Thiophenes,Azoles and Azines with Potential Biological Activity by Employing the Versatile Heterocyclic Precursor N‐Benzoycyanoacetylhydrazine

This research work is concerned with the use of N‐benzoyl cyanoacetylhydrazine ( 3 ) in synthesizing several new heterocyclic compounds with potential biological activity, via its reaction with various chemical reagents. The synthesized derivatives have actually exhibited, upon screening, antibacterial and antifungal activities.     

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.     

Mild and Ecofriendly Tandem Synthesis,and Spectral and Antimicrobial Studies of N1-Acetyl-5-aryl-3-(substituted styryl)pyrazolines

N¹-acetyl-5-aryl-3-(substituted styryl)pyrazolines were synthesized by the cyclocondensation of 1,5-substituted diphenyl-1,4-pentadien-3-ones with hydrazine hydrate and a cyclizing agent such as acetic acid in ethanol. The title compounds were synthesized using conventional and solvent-free approaches, which involves mechano-chemical mixing, microwave-irradiation, and ultrasound-irradiation methods in the presence of a solid support. The synthesized compounds have been characterized by elemental analyses and spectral data (IR, PMR, and FAB-mass). All the synthesized compounds have been evaluated for their antibacterial and antifungal activities. Some compounds have shown promising biological activity.     

Green Synthesis of Fused Imidazo[1,2‐a][1,8]naphthyridine Derivatives Catalyzed by DABCO under Solvent‐Free Solid‐State Conditions and Their Biological Evaluation

An efficient and eco‐friendly methodology has been developed for the construction of fused imidazo[1,2‐a][1,8]naphthyridine derivatives in the presence of 1,4‐diazabicyclo[2.2.2]octane, and involving various substituted heterocyclic amines with phenacyl bromide under solvent‐free solid‐state condition obtained the corresponding compounds ( 5a–g , 7a–f ) in short reaction time with high yield which is the important features of this protocol. All newly synthesized products were evaluated for their antibacterial and fungal activities. All these compounds displayed good antibacterial and antifungal activity. In predominantly, compounds 7e , 7d , and 5d demonstrate the highest antibacterial and antifungal activities. Furthermore, in silico molecular docking studies results were well complemented to the antimicrobial activity.     

Synthesis,Characterization and Biological Activities ofN-Acyl-3-(3-pyridyl)-5-aryl-pyrazoles

Ten novel N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles were synthesized by Claisen condensation of the aryl methyl ketones with ethyl nicotinate, the cyclization with hydrazine hydrate and the N-acylation with acyl chloride in turn. The structures of all the compounds synthesized were confirmed by means of Fourier transform infrared(FTIR), ¹H NMR, mass spectroscopy and elemental analysis. The biological activities of the title compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles exhibited a certain degree of antibacterial and antifungal activities. Comparatively, compounds 3c and 3d exhibited much significant antibacterial and antifungal activities than the other pyrazole derivatives.     

DCC/DMAP mediated esterification of hydroxy and non-hydroxy olefinic fatty acids with β-sitosterol:In vitro antimicrobial activity

<正>A new series of fatty alkenoates were synthesized using an appropriate synthetic route involving DCC and DMAP as catalysts. Compounds were characterized by their spectral data.All the synthesized compounds were evaluated for their in vitro antimicrobial activity.The minimum inhibitory concentration(MIC),minimum bacterial concentration(MBC) and minimum fungicidal concentration(MFC) were determined for test compounds as well as for reference standards.Among the compounds tested, compounds having hydroxy group at the fatty acid chain showed the most potent antibacterial as well as antifungal activities.     

Design,synthesis, characterization and antimicrobial evaluation of some novel hydrazinecarbothioamide, 4-thiazolidinone and 1,2,4-triazole-3-thione derivatives

A series of novel hydrazinecarbothioamide ( 5a,c,f ), 4-thiazolidinone ( 6a - e ), and 1,2,4-triazole-3-thione ( 7a - d ) were designed and synthesized. The structural elucidations of the novel compounds were performed by IR, ¹H-NMR, ¹³C-NMR, mass and elemental analysis. All novel derivatives were evaluated for their antibacterial and antifungal activities against nine diverse microorganisms. According to the biological activity studies of the compounds, 6d , 7c and 7d displayed hope promising antibacterial activity. Furthermore, 6d displayed potent antifungal activity. Consequently, the obtained results revealed that 6d , 7c and 7d present a leading structure for future drug development due to its straightforward synthesis and relevant bioactivity.     

Synthesis, biological and computational study of new Schiff base hydrazones bearing 3-(4-pyridine)-5-mercapto-1,2,4-triazole moiety

A series of new Schiff base hydrazones (compounds 1-16) were synthesized by condensation reaction of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole with various aldehydes and/or dialdehydes. The structure of the prepared compounds was confirmed by means of 1H NMR, 13C NMR, UV-vis, IR and elemental analyses. The all prepared compounds were assayed for antibacterial (Escherichia coli and Staphylococcus aureus) and antifungal (Candida albicans) activities by disc diffusion method. The results indicate that all tested compounds did not show any antibacterial activity against E. coli, as gram negative bacteria, and antifungal activity against C. albicans. But the compounds 2, 3, 4, 6 and 8 containing 4-Cl, 4-Me, 4-MeO, 2,4-di-Cl and 2-OH substituted phenyl moiety, respectively, showed good inhibition against S. aureus as compare to standard drugs. The structure of all biologically active compounds has also been theoretically studied by ab initio Hartree-Fock (HF) methods.     

Synthesis,antimicrobial activity,and molecular docking study of formylnaphthalenyloxymethyl‐triazolyl‐N‐phenylacetamides

In the present study, substituted formylnaphthalenyloxymethyl‐triazolyl‐N‐phenylacetamide derivatives ( 6a – k ) have been designed and synthesized employing click chemistry approach and evaluated for their in vitro antifungal and antibacterial activities. All the newly synthesized compounds were thoroughly characterized by ¹H NMR, ¹³C NMR, and HRMS spectral techniques. Among the screened compounds, 6d , 6e , 6j , and 6k have shown good antifungal and antibacterial activities. Compound 6k has shown very effective antimicrobial activity. We further performed exploratory docking studies on microbial DNA gyrase to rationalize the in vitro biological data and to demonstrate the mechanism of antimicrobial activity. This is the first report to demonstrate the formylnaphthalenyloxymethyl, triazole, and N‐phenylacetamide hybrids as potential antimicrobial agents.     

Synthesis,Docking, and Evaluation of Antimicrobial Activity of a New Series of Acyclo C‐Nucleosides of 1, 2, 4‐Triazolo[4, 3‐a]quinoxaline Derivatives

In this study, 18 new 3‐benzylquinoxalinyl hydrazones bearing carbohydrate moiety and their corresponding triazoloquinoxalines were synthesized in order to investigate their possible antibacterial and antifungal activities. Some of these compounds such as 4b , 4c , 7b , 7c , and 7d showed promising antibacterial and antifungal activities and were found to have more potent activity compared with that of standard drugs. From structure–activity relationship point of view, increasing the size of the substitutions at position 6 or 7 on the quinoxaline nucleus decreased the antimicrobial activity, while the presence of the hydroxyl groups at C2 (R) and C3 (S) of sugar moieties enhanced the activity. Further, molecular docking studies of the active compounds were performed on different targets belonging to different microorganisms and showed good scoring with further understanding of the various interactions with the active sites of interesting enzymes compared with the co‐crystallized ligands.