Design,Synthesis, Antimicrobial Evaluation,and Laccase Catalysis Effect of Novel Benzofuran–Oxadiazole and Benzofuran–Triazole Hybrids

Novel structural hybrids of benzofuran–oxadiazole and benzofuran–triazole have been synthesized and evaluated for their potential against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. The excellent antibiotic activity was shown by compounds 5c and 9c against S. aureus with minimum inhibitory concentration values in 1.74–5.16 mg/mL range. The estimation of in vitro antifungal activity of synthetic compounds was performed against Trichoderma harzianum, Aspergillus niger, and Metarhizium anisopliae. Among compounds 5a – 5j , only 5h and 5i showed promising antifungal potential against T. harzianum and A. niger, whereas compound 5j showed enhanced antifungal effect only against A. niger when their activity values were compared with standard drug amphotericin. No pronounced antifungal activity was shown by synthesized compounds 9a–j , except for compound 9g , which was active against all fungal strains having minimum inhibitory concentration values in 1.90–2.03 mg/mL range. In addition to antimicrobial evaluation, the synthesized compounds were also analyzed to study their effects on the catalytic potential of laccase, and it was found that among all, compound 9b showed very strong activity with maximum relative reactivity of 145% at 0.03‐mM concentration.     

Synthesis of Novel 1‐(5‐(Benzylsulfinyl)‐3‐methyl‐1,3,4‐thiadiazol‐2(3H)‐ylidene)‐thiourea/urea Derivatives and Evaluation of Their Antimicrobial Activities

A new series of 1‐(5‐(benzylsulfinyl)‐3‐methyl‐1,3,4‐thiadiazol‐2(3H)‐ylidene)‐thiourea/urea derivatives ( 1a – j ) were designed and synthesized. For the first time, (i) a new process was developed for N‐methylation of 1,3,4‐thiadiazole moiety using dimethyl carbonate an environmentally benign reagent in presence of N,N,N′,N′‐tetramethylethylenediamine and (ii) the sulfide was selectively oxidized to sulfoxide in higher yield by using chlorine (g) in aqueous acetic acid media under mild reaction condition. The synthesized compounds ( 1a – j ) were investigated for their antimicrobial activities. The tested compounds ( 1a – j ) were exhibited moderate to excellent antibacterial activities against both Gram‐positive and Gram‐negative bacterial strains. The same compounds exhibited good antifungal activities against selected fungal strains. Particularly, the compounds 1b , 1d , 1h , and 1i were proved to be promising leads exhibiting both antibacterial and antifungal activities compared with standard drugs, ciprofloxacin, and fluconazole. The presence of 1,3,4‐thiadiazole moiety has a significant role in the display of antimicrobial activity. In addition, the presence of both sulfinyl and thiourea or urea functionalities has enhanced the activity as per obtained antimicrobial activity data.     

A Facial Synthesis and Anticancer Activity of (Z)‐2‐((5‐(4‐nitrobenzylidene)‐4‐oxo‐4,5‐dihydrothiazol‐2‐yl)amino)‐substituted Acid

In order to explore the anticancer and antimicrobial activity associated with the thiazole framework, we synthesized the new series (Z )‐2‐((5‐(4‐nitrobenzylidene)‐4‐oxo‐4,5‐dihydrothiazol‐2‐yl)amino)‐substituted acid derivatives 6a – l . All the synthesized compounds were evaluated for anticancer and antimicrobial activity in vitro. Among these, the compounds 6a , 6b, 6c , 6e , 6f , 6g , 6h , 6i , 6j , and 6k showed highest antibacterial and antifungal activity. The compound 6a exhibited significant antibacterial activity against Bacillus subtilis , whereas compound 6j displays significant antifungal activity against fungal strains, that is, A. oryzae . The in vitro anticancer studies revealed that 6e , 6g , 6h , 6k , and 6l are the most active compounds against MCF‐7 and BT‐474 human breast cancer cell lines, which can be regarded as the promising drug candidate for development of anticancer drugs.     

Isomannide monoundecenoate-based 1,2,3-triazoles: Design,synthesis, and in vitro bioactive evaluation

A new series of isomannide monoundecenoate-based 1,2,3-triazole analogs 6a–e were designed by employing click chemistry in good yields. in vitro bioactive assay manifested that the several target compounds exhibited promising antibacterial and antifungal activities. Notably, compounds having phenyl substituted triazole 6a , and hydroxy phenyl substituted triazole 6b possessed highly selective promising inhibition towards Gram-positive bacterial strains namely Bacillus subtilis and Staphylococcus aureus with MIC value of 3.9 μg/mL. Further, these potential hybrids ( 6a and 6b) also exhibited highly impressive antifungal activity against the tested panel of Candida strains with MIC value of 3.9 μg/mL. Based on our in vitro preliminary antimicrobial study, these two compounds 6a and 6b have been identified as potential antimicrobial lead compounds. Moreover, all prepared derivatives were also evaluated for their in vitro cytotoxic activities against A549, MCF7, DU145 and HeLa cancer cell lines. The results indicated that only the hydroxy phenyl substituted triazole analog 6b displayed good cytotoxic activity towards all tested human cancer cell lines without any significant effects on normal cell line (HUVEC).     

Design,synthesis and biological activity against estrogen receptor-dependent breast cancer of furo[1]benzofuran derivatives

The docking study on a series of furo[1]benzofuran derivatives with ERα has been demonstrated. The synthesis and characterization of a series of furo[1]benzofuran derivatives were described. All the target compounds were conducted to in vitro for the inhibitory activities against human breast cancer strains T-47D, MCF-7 and toxicity against human liver normal cell strains HL7702 via MTT assay. Most of the target compounds possessed anti-estrogen receptor-dependent breast cancer activities with weak toxicity to healthy cell strains. The preliminary structure–activity relationships were discussed.     

Synthesis and In Vitro Antimicrobial Activity of 1,3,4‐Oxadiazole‐2‐thiol and its Analogs

The present communication deals with the synthesis of 1,3,4‐oxadiazole‐2‐thiol derivatives containing cyclic secondary amines such as morpholine, N‐methyl piperizine, and piperizine. The structural elucidation is based on the spectral data (IR, ¹H NMR, and ¹³C NMR) .The newly synthesized compounds were then tested for their antimicrobial activity against a representative panel of micro‐organisms such as Bacillus subtilis, Escherichia coli and Candida albicans by using ciprofloxacin and fluconazole as reference drugs for bacteria and fungi, respectively. These synthesized compounds showed moderate to potential antibacterial and antifungal activity in the range of 6–50 μM against the selected bacteria and 12–50 μM against the most common fungi, respectively.     

Synthesis and Antimicrobial Evaluations of Some Novel Mono‐, Bis‐, and Tris‐Nitro‐1,2,4‐Triazines

Substituted‐1,2,4‐triazines were conveniently synthesized in one pot by the cyclization of arylnitroformaldehyde hydrazone derivatives 1 and 5 with different primary amines in ~37% formaldehyde solution. The synthesized compounds were arranged into novel mono‐, bis‐, and tris‐nitro‐1,2,4‐triazine derivatives 2 , 3 , 4 , 6 , and 7 . The antibacterial and antifungal activity of the synthesized compounds were screened against bacterial strains Escherichia coli (as Gram − ve) and Staphylococcus aureus (as Gram + ve), and fungal strains Aspergillus flavus and Candida albicans . All the synthesized compounds exhibit various patterns of inhibitory activity on the two pathogenic bacterial strains. However, the same compounds showed no activity against the tested fungal strains.     

Design,Synthesis, and In Vitro Anti‐mycobacterial Activities of Propylene Tethered Benzofuran–Isatin Hybrids

A series of novel propylene tethered benzofuran–isatin hybrids 5a–j were designed, synthesized, and assessed for their in vitro anti‐mycobacterial activity against Mycobacterium tuberculosis (MTB) H₃₇Rv and multidrug‐resistant (MDR)‐MTB strains. All hybrids exhibited promising anti‐mycobacterial activities against the tested two pathogens with minimum inhibitory concentration (MIC) ranging from 2 to 32 μg/mL, and the resistance index for a significant part of the hybrids was ≤1, indicating their potential for the treatment of drug‐resistant tuberculosis. Hybrid 5g (MIC: 2 and 4 μg/mL) was found to be the most active against MTB H₃₇Rv and MDR‐MTB, which was eightfold and >32‐fold more active than the first‐line anti‐tuberculosis drugs rifampicin (MIC: 32 μg/mL) and isoniazid (MIC: >128 μg/mL) against MDR‐MTB, and it could act as a starting point for further optimization.     

Synthesis and Antimicrobial Evaluation of Novel Derivatives of Semicarbazide and 1,2,4‐triazole

Reaction of phenoxyacetic acid hydrazide with isocyanate was used to the synthesis of new semicarbazide derivatives. Cyclization of these compounds in a 2% aqueous solution of sodium hydroxide led to formation of 1,2,4‐triazole‐3‐one. The chemical structure of synthesized compounds was confirmed by elemental analysis and spectroscopic methods (¹H and ¹³C NMR). On the basis of the NMR, spectra were found that cyclic compounds 1,2,4‐triazole exist in the ‐one form. Moreover, all derivatives were examined for their in vitro activity against some species of bacteria. New compounds presented mild or moderate antimicrobial activity only against reference Gram‐positive bacteria. Two derivatives (one semicarbazide and one triazole) showed bactericidal or bacteriostatic activity.     

Design,synthesis and antifungal activity of novel selenochroman-4-one derivatives

A series of novel selenochroman-4-one derivatives bearing semicarbazone or nitrogen heterocycle was designed, synthesized, tested antifungal activity and characterized via ¹H-NMR, ¹³C-NMR, and HRMS. The design of the compounds is based on the principle of molecule hybrid and bioisosterism. We aimed at attaching semicarbazones or nitrogen heterocycle to the selenochroman-4-one for enhancing antifungal activity. The antifungal activity of target compounds was evaluated using the microdilution broth method in vitro test. Bioassay results indicated that some of the derivatives displayed good fungistatic activity on Candida zeylanoides, Candida albicans, Cryptococcus neoformans, resistant to fluconazole strain 103 (Candida albicans), resistant to fluconazole strain 100 (Candida albicans) and strain SC5314 (Candida albicans). All the compounds exhibit antifungal activities against the tested funguses in different levels, among them, 7 compounds of antifungal activity against several funguses is better than that of the control drug fluconazole. Based on the results, preliminary structure activity relationships (SARs) were summarized to serve as a foundation for further investigation.     

Synthesis,Antimicrobial Activity and Molecular Docking Studies of 1,3‐Thiazole Derivatives Incorporating Adamantanyl Moiety

Synthesis, characterization and investigation of antimicrobial activity of 11 novel adamantanyl‐thiazoles are presented. Their structures were determined using ¹H and ¹³C NMR, EI(+)‐MS, HRMS, and elemental analyses. Among the derivatives, compound 3c showed very strong activity, especially against Candida albicans ATCC 10231 and Candida parapsilosis ATCC 22019 with minimal inhibitory concentration (MIC) values ranging from 1.95 to 7.81 µg/ml. Compounds 3a and 3b showed good antifungal activity. Among the examined compounds, the widest spectrum of antibacterial activity possessed 3f that showed good activity, especially against Staphylococcus epidermidis ATCC 12228, Micrococcus luteus ATCC 10240, Bacillus subtilis ATCC 6633 with MIC values ranging from 31.25 to 62.5 µg/ml. Molecular docking studies of all compounds on the active sites of microbial enzymes indicated possible targets sterol 14α‐demethylase, secreted aspartic proteinase (SAP), N‐myristoyltransferase (NMT), and topoisomerase II. Thiazoles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k showed more favorable affinity to SAP and NMT than the native ligand.     

Synthesis,Characterization, and Antimicrobial Screening of 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole Derivatives

A series of novel 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole ( 8a‐p ) derivatives has been synthesized and screened for antibacterial activity against four pathogenic bacteria, Escherichia coli, Pseudomonas flurescence, Staphylococcus aureus, and Bacillus subtilis. Among them, compounds 8a and 8j exhibited excellent antibacterial activity with minimum inhibitory concentration range of 1.0 to 5.3 μg/mL and compounds 8m and 8p exhibited moderate to good antibacterial activity with minimum inhibitory concentration range of 16.9 to 29.7 μg/mL against all tested strains. All the synthesized compounds were screened for their in vitro antifungal activity against Cocinida candida. Most of the compounds reported moderate antifungal activity. This study provides valuable directions to our ongoing endeavor of rationally designing more potent antimicrobial agent.     

Novel Pyrazoline‐based Organometallic Compounds Containing Ferrocenyl and Quinoline units: Synthesis,Characterization and Microbial susceptibilities

Some novel pyrazoline‐based organometallic compounds were synthesized as new leads in antimicrobial chemotherapy. The structures of compounds were elucidated by different spectroscopic techniques and elemental analyses. All compounds were investigated for in vitro antimicrobial studies against fifteen ATTC bacterial and fungal strains. The microbial susceptibility of these compounds revealed that all the tested compounds gave good minimum inhibitory concentration (MIC) values against the tested organisms that are either similar or even better than the reference drugs amoxicillin and fluconazole, which gave MIC values 8‐64 μg/ml against bacterial and 64 μg/ml against fungal strains, respectively. Among all compounds, compound ( 4d ) 1‐(5‐(4‐chlorophenyl)‐3‐ferrocenyl‐4,5‐dihydropyrazol‐1‐yl)‐2‐quinolin‐8‐yloxy) ethanone, emerged out the most promising antimicrobial organometallic derivative with MIC values against all the strains ranging from 8‐32 μg/ml. Other compounds gave a range of MIC values between 16‐64 μg/ml against S. bovis, 16‐32 μg/ml against E. coli, and C. tropicalis except compound ( 4d) which gave MIC 8 μg/ml against S. bovis and E. coli, whereas 32 μg/ml against C. tropicalis. Collectively, these compounds gave a lower MIC value between 32‐64 μg/ml against both of the biofilm forming strains namely, P. aeruginosa and S. mutans. The results of microbial susceptibility concluded that these novel organometallic compounds are new leads in antimicrobial chemotherapy and can be very useful for further optimization work on microbial chemotherapy.     

Design and Synthesis of New Aryloxy‐linked Dimeric 1,2,3‐Triazoles via Click Chemistry Approach: Biological Evaluation and Molecular Docking Study

A quest for more potent new antitubercular agents has prompted to design and synthesize aryloxy‐linked dimeric 1,2,3‐triazoles ( 4a – j ), from azides ( 2a‐e ) and bis(prop‐2‐yn‐1‐yloxy)benzene ( 3a – b ) on 1,3‐dipolar cycloaddition reaction via copper (I)‐catalyzed click chemistry approach with good to better yields. The titled compounds ( 4a – j ) were designed using molecular hybridization approach by assembling various bioactive pharmacophoric fragments in a single molecular framework. All the synthesized compounds have been screened for their in vitro antitubercular, antifungal, and antioxidant activities against their respective strains. Among them, 4h and 4i show the highest antifungal activity, whereas compounds 4h , 4i , and 4j have revealed promising antitubercular activity against their respective strains. In addition to this, most of the synthesized compounds were found as potent antifungal and antioxidant agents. A significant network of bonded and non‐bonded interactions stabilized these molecules into the active site of fungal CYP51 that is realized from the obtained well‐placed docking poses and the associated thermodynamic interactions with the enzyme. The synthesized compounds have also been analyzed for absorption, distribution, metabolism, and excretion properties.     

Synthesis,characterization and biological properties of sulfonamide‐derived compounds and their transition metal complexes

Sulfonamide‐derived compounds and their first row d‐transition metal chelates [cobalt(II), copper(II), nickel(II) and zinc(II)] have been synthesized and characterized. The nature of bonding and structure of all the synthesized compounds have been proposed from magnetic susceptibility and conductivity measurements, IR, ¹H and ¹³C NMR, electron spectra, mass spectrometry and CHN analysis data. The structure of ligand, 4‐{[(E)‐(5‐chloro‐2‐hydroxyphenyl) methylidene] amino}‐N‐(4,6‐dimethyl pyrimidin‐2‐yl) benzene sulfonamide has also been determined by X‐ray diffraction method. An octahedral geometry has been suggested for all the complexes. The ligands and metal complexes have been screened for their in vitro antibacterial, antifungal and cytotoxic activity. The results of these studies revealed that all compounds showed moderate to significant antibacterial activity against one or more bacterial strains and good antifungal activity against various fungal strains. Copyright © 2009 John Wiley & Sons, Ltd.     

Isatin‐(thio)semicarbazide/oxime‐1H‐1,2,3‐triazole‐coumarin Hybrids: Design,Synthesis, and in vitro Anti‐mycobacterial Evaluation

Isatin and coumarin derivatives with potential anti‐tubercular activity, while (thio)semicarbazide/oxime and 1H‐1,2,3‐triazole moieties exhibited favorable properties such as hydrogen bonding and/or metal chelation capability, so integration of the four pharmacophores into one molecule may provide more effective anti‐tubercular candidates. Based on the consideration earlier, 12 isatin‐(thio)semicarbazide/oxime‐1H‐1,2,3‐triazole‐coumarin hybrids 8a–l were designed, synthesized, and evaluated for their in vitro anti‐mycobacterial activities against M. tuberculosis (MTB) H₃₇Rv and MDR‐TB. The results showed that all the hybrids (MIC: 50–>200 μg/mL) exhibited weak to moderate inhibitory activity against MTB H₃₇Rv and MDR‐TB, which were far less potent than the references isoniazid (MIC: 0.05 μg/mL) and rifampicin (MIC: 0.39 μg/mL) against MTB H₃₇Rv. The most active hybrid 8h (MIC: 50 μg/mL) was comparable with rifampicin (MIC: 32 μg/mL) and more active than isoniazid (MIC: >128 μg/mL) against MDR‐TB, could be act as a lead for further optimization. Moreover, the enriched structure–activity relationship paved the way to the further rational development of this kind of hybrids.     

Benzofuran–isatin Hybrids: Design,Synthesis, and In Vitro Anti‐cancer Activities

A series of novel benzofuran–isatin hybrids 6a – s tethered through propylene and butylene were designed, synthesized, and evaluated for their in vitro anti‐cancer activities against HepG2 (liver carcinoma), Hela (cervical cancer), A549 (lung adenocarcinoma), DU145 (prostatic cancer), SKOV3 (ovarian carcinoma), MCF‐7 (breast cancer), and drug‐resistant MCF‐7/DOX (doxorubicin‐resistant MCF‐7) human cancer cell lines. The majority of the synthesized hybrids displayed weak to moderate in vitro activities against the tested seven cancer cell lines, but the enriched structure–activity relationship may pave the way for further optimization.     

Design,Synthesis, and Evaluation of Some Novel Heterocycles Bearing Pyrazole Moiety as Potential Anticancer Agents

1,3‐Diphenylpyrazole‐4‐carboxylaldehyde and o‐hydroxyacetophenone were exploited as starting materials for the synthesis of novel substituted chalconated pyrazole derivative. The proclivity of this compound towards carbon and nitrogen nucleophiles such as malononitrile, diethyl malonate, ethyl cyanoacetate, ethyl acetoacetate, semicarbazide, thiosemicarbazide, and hydroxylamine has been investigated. The structures of all synthesized compounds were ascertained by analytical and spectral data. The antitumor activity of the target synthesized compounds was tested against a panel of two human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2 and mammary gland breast MCF‐7.     

Arylpyrazole as selective anti-enterococci; synthesis and biological evaluation of novel derivatives for their antimicrobial efficacy

Exploring the structure–activity relationships (SAR) of a new set of phenylpyrazoles unveiled a potential anti-enterococcus lead compound 12 . The benzofuran moiety linked to the phenylpyrazole 12 was 32 times better than vancomycin against Enterococcus faecalis ATCC 51299. Besides, compound 12 is expected to have an excellent oral bioavailability according to the in silico studies. Of SAR analysis, we found that the benzofuran side chain was essential for the activity. Changing the benzofuran with either benzothiophene, phenyl, pyridinyl, tolyl, or naphthyl reduces/nullifies the pharmacological action. Besides the anti-enterococcal activity, derivatives 4 and 6 can be used to develop new broad-spectrum antibiotics as they exhibited activity against the wild-type highly virulent Escherichia coli isolate. Moreover, compound 13 was proved to show antifungal activity (MIC = 4 μg/ml) against the Candida albicans SS5314 (wild type). Finally, the in silico analysis showed that those compounds have good profiles regarding the absorption, distribution, metabolism, and excretion studies, drug-likeness and pharmacokinetics properties.     

Synthesis and Antimicrobial Evaluation of Novel Dibenzo‐18‐Crown‐6‐Ether Functionalized Pyrimidines

A practical, two‐step synthesis of crown ether functionalized pyrimidines has been developed. The reaction conditions have been optimized, and the protocol is generalized for series of substrates. These newly synthesized compounds exhibited antimicrobial activity against bacterial strains Staphylcoccus aureus (Gram‐positive) and Escherichia coli (Gram‐negative). These compounds were also found to be potent antifungal agents Aspergillus niger and Candida albicans strains, respectively.