- Multi-activity tetracoordinated pallado-oxadiazole thiones as anti-inflammatory, anti-Alzheimer, and anti-microbial agents: Structure, stability and bioactivity comparison with pallado-hydrazides
-
Herein, we report a comparative study based on structure, thermal and solution stability, and biopotency against lipoxygenase (LOX), butyrylcholinesterase (BChE) and microbes for Pd(II) compounds of N,O,S bearing 5-(C5H4XR)-1,3,4-oxa
- Abid, Aisha,Eijaz, Sana,Lateef, Mehreen,Qurrat-ul-Ain,Rafiq, Naushaba,Tauseef, Saima
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- Synthesis and Biological Evaluation of Oxadiazole Clubbed Thiadiazole Derivatives as Antimicrobial Agents
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A series of 1,3,4-oxadiazole clubbed 1,3,4-thiadiazole derivatives were synthesized and assessed in vitro for their activity as antimicrobial agents. The target compounds 2-(5-(substituted aryl)-1, 3, 4-oxadiazol-2-ylthio)-N-(5-(substituted aryl)-1, 3, 4-thiadiazol-2-yl) acetamides (5a-5s) were synthesized using a basic condensation reaction between 5-(substituted aryl)-1,3,4-oxadiazole-2-thiol and 2-chloro-N-(5-(substituted aryl)-1,3,4-thiadiazol-2-yl)acetamide in presence of K2CO3 as a scavenging agent and acetone as reaction solvent. The titled compounds synthesized here, exhibited excellent to moderate antimicrobial activity against a broad panel of antibacterial strains of Gram-positive and Gram-negative bacteria and fungi.
- Begari, Eeshwaraiah,Dave, Alpa Y.,Joshi, Deepkumar S.,Parmar, Kokila A.
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p. 273 - 280
(2021/08/03)
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- Antibacterial and Antiviral Activities of 1,3,4-Oxadiazole Thioether 4H-Chromen-4-one Derivatives
-
Various 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives were conceived. The title compounds demonstrated striking inhibitory effects againstXac,Psa, andXoo. EC50data exhibited that A8 (19.7 μg/mL) had better antibacterial activity againstXoothan myricetin, BT, and TC. Simultaneously, the mechanism of action of A8 had been verified by SEM. The results of anti-tobacco mosaic virus indicated that A9 had the bestin vivoantiviral effect compared with ningnanmycin. From the data of MST, it could be seen that A9 (0.003 ± 0.001 μmol/L) exhibited a strong binding capacity, which was far superior to ningnanmycin (2.726 ± 1.301 μmol/L). This study shows that the 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives may become agricultural drugs with great potential.
- Cao, Xiao,Liu, Fang,Liu, Liwei,Liu, Tingting,Peng, Feng,Wang, Qifan,Xie, Chengwei,Xue, Wei,Yang, Jinsong
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p. 11085 - 11094
(2021/10/01)
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- Design, synthesis, in vitro and in vivo evaluation against MRSA and molecular docking studies of novel pleuromutilin derivatives bearing 1, 3, 4-oxadiazole linker
-
A class of pleuromutilin derivatives containing 1, 3, 4-oxadiazole were designed and synthesized as potential antibacterial agents against Methicillin-resistant staphylococcus aureus (MRSA). The ultrasound-assisted reaction was proposed as a green chemistry method to synthesize 1, 3, 4-oxadiazole derivatives (intermediates 85–110). Among these pleuromutilin derivatives, compound 133 was found to be the strongest antibacterial derivative against MRSA (MIC = 0.125 μg/mL). Furthermore, the result of the time-kill curves displayed that compound 133 could inhibit the growth of MRSA in vitro quickly (- 4.36 log10 CFU/mL reduction). Then, compound 133 (- 1.82 log10 CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (- 0.82 log10 CFU/mL) in reducing MRSA load in mice thigh model. Besides, compound 133 exhibited low cytotoxicity to RAW 264.7 cells. Molecular docking studies revealed that compound 133 was successfully localized in the binding pocket of 50S ribosomal subunit (ΔGb = -10.50 kcal/mol). The results indicated that these pleuromutilin derivatives containing 1, 3, 4-oxadiazole might be further developed into novel antibiotics against MRSA.
- Liu, Jie,Zhang, Guang-Yu,Zhang, Zhe,Li, Bo,Chai, Fei,Wang, Qi,Zhou, Zi-Dan,Xu, Ling-Ling,Wang, Shou-Kai,Jin, Zhen,Tang, You-Zhi
-
-
- Pleuromutilin derivative with 1, 3, 4-oxadiazole side chain and preparation and application thereof
-
The invention belongs to the field of medicinal chemistry, and particularly relates to a pleuromutilin derivative with a 1, 3, 4-oxadiazole side chain and preparation and application thereof The pleuromutilin derivative with the 1, 3, 4-oxadiazole side chain is a compound shown in a formula 2 or a pharmaceutically acceptable salt thereof, and a solvent compound, an enantiomer, a diastereoisomer and a tautomer of the compound shown in the formula 2 or the pharmaceutically acceptable salt thereof or a mixture of the solvent compound, the enantiomer, the diastereoisomer and the tautomer in any proportion, including a racemic mixture. The pleuromutilin derivative has good antibacterial activity, is especially suitable for being used as a novel antibacterial agent for systemic system infection of animals or human beings, and has good water solubility.
- -
-
Paragraph 0055-0056; 0070; 0090; 0094; 0095; 0103
(2021/07/24)
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- Synthesis, antifungal and antibacterial activity of calix[4]arene-based 1,3,4-oxadiazole derivatives
-
We describe the synthesis of some novel p-tert-butylcalix[4]arene-based (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate derivatives (4a–e). These compounds were synthesized by the reaction of tetra-tert-butyl calix[4]arene (1) with (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate (3a–e) in the presence of potassium carbonate as a weak base and dry acetone as the solvent. All the newly synthesized calix[4]arene derivatives were characterized by elemental analysis and various spectroscopic methods such as FT-IR, 1H NMR,13C NMR, DEPT, and ESI-MS. The synthesized compounds were tested in vitro for their antibacterial and antifungal activities against Escherichia coli and Aspergillus fumigates in comparison with enrofloxacin and amphotericin as reference drugs, which are normally used for treating such infections. The synthesized compounds showed different inhibition zones against the tested bacteria and fungi. Compound 4c was found to be most effective against A. fumigates, whereas compound 4e was found to be equally effective against E. coli and A. fumigates.
- Dono Gezelbash, Zahra,Akbari Dilmaghani, Karim
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p. 1446 - 1452
(2020/03/11)
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- Synthesis, characterization, and nonlinear optical properties of some new series of S-(5-aryl-1,3,4-oxadiazol-2-yl) 2-chloroethanethioate derivatives
-
In the present investigation, some novel S-(5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate (3a–3e) derivatives were synthesized and their impact on optical properties was studied. They have also been characterized by elemental analysis and various spectroscopic methods including FTIR, 1 H NMR, 13 C NMR, and UV-Vis techniques. The nonlinear refractive indexes of 3a–3e were also measured in dichloromethane via Z-scan method using a continuous wave diode-pumped laser at 532 nm wavelength. The nonlinear refractive coefficient of compounds was obtained from 1011 m2/W order. Regarding the appropriate nonlinearity of these compounds, they could be considered good candidates for biooptical and photonic applications. All the synthesized compounds (3a–3e) have also been evaluated for their antimicrobial and antifungal activities. The bioactive assay showed that the synthetic compounds displayed variable inhibition zones against tested bacterium Escherichia coli and fungus Aspergillus fumigatus in comparison to enrofloxacin and amphotericin as reference drugs, which are normally used for treating such infections.
- Ghezelbash, Zahra Dono,Motiei, Hamideh,Mahmoody, Miri,Dilmaghani, Karim Akbari
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p. 902 - 910
(2019/07/17)
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- Rational Optimization and Action Mechanism of Novel Imidazole (or Imidazolium)-Labeled 1,3,4-Oxadiazole Thioethers as Promising Antibacterial Agents against Plant Bacterial Diseases
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The emergence and widespread occurrence of plant bacterial diseases that cause global production constraints have become major challenges to agriculture worldwide. To promote the discovery and development of new bactericides, imidazole-labeled 1,3,4-oxadiazole thioethers were first fabricated by integrating the crucially bioactive scaffolds of the imidazole motif and 1,3,4-oxadiazole skeleton in a single molecular architecture. Subsequently, a superior antibacterial compound A6 was gradually discovered possessing excellent competence against plant pathogens Xanthomonas oryzae pv oryzae and Xanthomonas axonopodis pv citri with EC50 values of 0.734 and 1.79 μg/mL, respectively. These values were better than those of commercial agents bismerthiazol (92.6 μg/mL) and thiodiazole copper (77.0 μg/mL). Further modifying the imidazole moiety into the imidazolium scaffold led to the discovery of an array of potent antibacterial compounds providing the corresponding minimum EC50 values of 0.295 and 0.607 μg/mL against the two strains. Moreover, a plausible action mechanism for attacking pathogens was proposed based on the concentration dependence of scanning electron microscopy, transmission electron microscopy, and fluorescence microscopy images. Given the simple molecular structures, easy synthetic procedure, and highly efficient bioactivity, imidazole (or imidazolium)-labeled 1,3,4-oxadiazole thioethers can be further explored and developed as promising indicators for the development of commercial drugs.
- Wang, Pei-Yi,Wang, Ming-Wei,Zeng, Dan,Xiang, Meng,Rao, Jia-Rui,Liu, Qing-Qing,Liu, Li-Wei,Wu, Zhi-Bing,Li, Zhong,Song, Bao-An,Yang, Song
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p. 3535 - 3545
(2019/03/26)
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- N-(5-Methyl-1,3-Thiazol-2-yl)-2-{[5-((Un)Substituted- Phenyl)1,3,4-Oxadiazol-2-yl]Sulfanyl}acetamides. Unique Biheterocycles as Promising Therapeutic Agents
-
An electrophile, 2-bromo-N-(5-methyl-1,3-thiazol-2-yl)acetamide, was synthesized by the reaction of 5-methyl-1,3-thiazol-2-amine and bromoacetyl bromide in an aqueous medium. In a parallel scheme, a series of (un)substituted benzoic acids was converted sequentially into respective esters, acid hydrazides, and then into 1,3,4-oxadiazole heterocyclic cores. The electrophile was coupled with the aforementioned 1,3,4-oxadiazoles to obtain the targeted bi-heterocyles. Structural analysis of the synthesized compounds was performed by IR, EI-MS, 1H NMR, and 13C NMR. The enzyme inhibition study of these molecules was carried out against four enzymes, namely, acetylcholinesterase, butyrylcholinesterase, α-glucosidase, and urease. The interactions of these compounds with respective enzymes were recognized by their in silico study. Moreover, their cytotoxicity was also determined to find out their utility as possible therapeutic agents.
- Abbasi,Ramzan,Aziz-ur-Rehman,Siddiqui,Shah,Hassan,Seo,Ashraf,Mirza,Ismail
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p. 801 - 811
(2019/02/27)
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- Synthesis, spectral analysis and antibacterial evaluation of 5-substituted-1,3,4-oxadiazol-2-yl 4-(4-methylpiperidin-1-ylsulfonyl)benzyl sulfides
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Owing to valuable biological activities of 1,3,4-oxadiazole, sulfamoyl and piperidine functionalities, some new 1-(4-{[(5-substituted-1,3,4-oxadiazol-2-yl) thio]methyl}benzene sulfonyl)-4-methylpiperidine (6a-o) derivatives have been introduced. The target molecules were synthesized from different aralkyl/aryl carboxylic acids, 1a-o, through a series of steps. First the compounds, 1a-o, were converted to heterocyclic 1,3,4-oxadiazole nucleophiles, 4a-o. Second an electrophile as 1-(4-bromomethylbenzenesulfonyl)-4-methylpiperidine (5) was synthesized from 4-methylpiperidine. Finally the target compounds, 6a-o, were prepared by reacting 4a-o with 5 in DMF and LiH. The final compounds were structurally elucidated by spectral data of IR, 1H-NMR and EI-MS. All the compounds were screened for their antibacterial evaluation and found to exhibit valuable results.
- Aziz-Ur-Rehman,Ahtzaz, Samreen,Abbasi, Muhammad Athar,Siddiqui, Sabahat Zahra,Rasool, Shahid,Ahmad, Irshad
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p. 3370 - 3375
(2017/05/22)
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- Synthesis and pharmacological screening: Sulfa derivatives of 2-pipecoline-bearing 1,3,4-oxadiazole core
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An electrophile, 1-(4-(bromomethylbenzenesulfonyl)-2-methylpiperidine, was synthesized by the reaction of 2-methylpiperidine (2-pipecoline) and 4-bromomethylbenzenesulfonyl chloride in a weak basic medium under pH control. A series of nucleophiles, 5-aryl/aralkyl-1,3,4-oxadiazol-2-thiols, were synthesized from corresponding carboxylic acids in three steps. The title molecules were synthesized by coupling the electrophile to nucleophiles in an aprotic medium using LiH as an activator. The structures of all synthesized compounds were corroborated through IR, 1H NMR, and EI-MS techniques. All the compounds were screened for their pharmacological behavior, particularly, antibacterial and enzyme inhibitory activities. Notably efficient results were obtained against both gram-positive and gram-negative bacterial strains. Regarding enzyme inhibition, compounds were efficient against acetylcholinesterase and butyrylcholinesterase.
- Aziz-ur-Rehman,Arif,Abbasi,Siddiqui,Rasool,Shah
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p. 328 - 339
(2017/07/04)
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- Synthesis of a series of novel tetra-tert-butylcalix[4]arene linked to 1,2,4-triazole and 1,3,4-oxadiazole derivatives
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A series of tetra-tert-butylcalix[4]arene linked to 1,2,4-triazole-5-thiones and 1,3,4-oxadiazole-5-thiones derivatives at lower rim were synthesized by the reaction of 1,2,4-triazole-5-thione and 1,3,4-oxadiazole-5-thione with 5,11,17,23-tetra-tert-butyl-25,27-bis(3-bromopropoxy)-26,28-dihydroxycalix[4]arene (2). The synthesized compounds were characterized by FT-IR, 1H NMR, 13C NMR spectral data, elemental analysis and ESI-MS.
- Ghezelbash, Zahra Dono,Dilmaghani, Karim Akbari
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p. 790 - 797
(2016/12/18)
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- Development of 3,5-Dinitrobenzylsulfanyl-1,3,4-oxadiazoles and Thiadiazoles as Selective Antitubercular Agents Active Against Replicating and Nonreplicating Mycobacterium tuberculosis
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Herein, we report the discovery and structure-activity relationships of 5-substituted-2-[(3,5-dinitrobenzyl)sulfanyl]-1,3,4-oxadiazoles and 1,3,4-thiadiazoles as a new class of antituberculosis agents. The majority of these compounds exhibited outstanding in vitro activity against Mycobacterium tuberculosis CNCTC My 331/88 and six multidrug-resistant clinically isolated strains of M. tuberculosis, with minimum inhibitory concentration values as low as 0.03 μM (0.011-0.026 μg/mL). The investigated compounds had a highly selective antimycobacterial effect because they showed no activity against the other bacteria or fungi tested in this study. Furthermore, the investigated compounds exhibited low in vitro toxicities in four proliferating mammalian cell lines and in isolated primary human hepatocytes. Several in vitro genotoxicity assays indicated that the selected compounds have no mutagenic activity. The oxadiazole and thiadiazole derivatives with the most favorable activity/toxicity profiles also showed potency comparable to that of rifampicin against the nonreplicating streptomycin-starved M. tuberculosis 18b-Lux strain, and therefore, these derivatives, are of particular interest.
- Karabanovich, Galina,Zemanová, Júlia,Smutny, Tomá?,Székely, Rita,?arkan, Michal,Centárová, Ivana,Vocat, Anthony,Pávková, Ivona,?onka, Patrik,Něme?ek, Jan,Stola?íková, Ji?ina,Vejsová, Marcela,Vávrová, Kate?ina,Klime?ová, Věra,Hrabálek, Alexandr,Pávek, Petr,Cole, Stewart T.,Miku?ová, Katarína,Roh, Jaroslav
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p. 2362 - 2380
(2016/04/09)
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- Rational design, synthesis and biological evaluation of 1,3,4-oxadiazole pyrimidine derivatives as novel pyruvate dehydrogenase complex E1 inhibitors
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On the basis of previous study on 2-methylpyrimidine-4-ylamine derivatives I, further synthetic optimization was done to find potent PDHc-E1 inhibitors with antibacterial activity. Three series of novel pyrimidine derivatives 6, 11 and 14 were designed and synthesized as potential Escherichia coli PDHc-E1 inhibitors by introducing 1,3,4-oxadiazole-thioether, 2,4-disubstituted-1,3-thiazole or 1,2,4-triazol-4-amine-thioether moiety into lead structure I, respectively. Most of 6, 11 and 14 exhibited good inhibitory activity against E. coli PHDc-E1 (IC50 0.97-19.21 μM) and obvious inhibitory activity against cyanobacteria (EC50 0.83-9.86 μM). Their inhibitory activities were much higher than that of lead structure I. 11 showed more potent inhibitory activity against both E. coli PDHc-E1 (IC50 50 50 = 0.97 μM) and cyanobacteria (EC50 = 0.83 μM). The possible interactions of the important residues of PDHc-E1 with title compounds were studied by molecular docking, site-directed mutagenesis, and enzymatic assays. The results indicated that 11d had more potent inhibitory activity than that of 14d or I due to its 1,3,4-oxadiazole moiety with more binding position and stronger interaction with Lsy392 and His106 at active site of E. coli PDHc-E1.
- He, Haifeng,Wang, Wei,Zhou, Yuan,Xia, Qin,Ren, Yanliang,Feng, Jiangtao,Peng, Hao,He, Hongwu,Feng, Lingling
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p. 1879 - 1888
(2016/04/05)
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- Synthesis, Antimicrobial Evaluation, and Structure Activity Relationship Studies of New Biphenyl-2-Carbonitrile Clubbed 1,3,4-Oxadiazole Derivatives
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Aseries of biphenyl-2-carbonitile clubbed 1,3,4-oxadiazole derivatives have been synthesized by the condensation of biphenyl-2-carbonitrile with various substituted 2-mercapto-5-aryl-1,3,4-oxadiazoles. Structures of the newly synthesized compounds IVa IVh were characterized using FTIR, 1H NMR, 13C NMR, mass spectroscopy, and elemental analysis. All the compounds were screened for their antimicrobial properties against a broad spectrum of bacteria and fungi. It was very clearly noted from SAR study that the derivatives bearing electron-withdrawing functional groups (-NO2, -Cl) were more promising than the derivatives with electron-donating group (-CH3) as antimicrobial agents.
- Parikh, Kalpesh,Joshi, Abhishek,Kshatriya, Rahulsingh,Joshi, Deepkumar
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p. 523 - 529
(2016/02/14)
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- Synthesis, Structural Analysis, and Screening of Some Novel 5-Substituted Aryl/Aralkyl-1,3,4-Oxadiazol-2-Yl 4-(Morpholin-4-Ylsulfonyl)Benzyl Sulfides As Potential Antibacterial Agents
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A series of new 5-substituted aryl/aralkyl-1,3,4-oxadiazol-2-yl 4-(morpholin-4-ylsulfonyl)benzyl sulfides 6a-k were synthesized by converting multifarious aryl/aralkyl organic acids 1a-k successively into corresponding esters 2a-k, hydrazides 3a-k, and 5-substituted aryl/aralkyl-1,3,4-oxadiazole-2-thiols 4a-k. Finally, the target compounds, 6a-k were prepared by stirring 5-substituted-1,3,4-oxadiazole-2-thiols with 4-(4-(bromomethyl)phenylsulfonyl) morpholine (5) in the presence of N,N-dimethylformamide (DMF) and sodium hydride (NaH). The structures of the newly synthesized compounds were elucidated by spectroscopic techniques. In addition, the antibacterial activity of all the synthesized compounds was investigated in vitro against Gram-positive and Gram-negative bacteria by using ciprofloxacin as reference standard drug and the results showed that some of the tested compounds possessed good antibacterial activity.
- Aziz-Ur-Rehman,Gul, Samreen,Abbasi, Muhammad Athar,Nafeesa, Khadija,Akhtar, Muhammad Nadeem,Ahmad, Irshad,Afzal, Saira
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p. 1045 - 1055
(2015/08/04)
-
- Synthesis and antimicrobial evaluation of 1,3,4-oxadiazole-based chalcone derivatives
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A series of chalcones-bearing 1,3,4-oxadiazole derivatives was synthesized as novel bio-active antimicrobial agents against multidrug-resistant bacteria and fungi. The lead compounds (Z)-2-(5-(3-nitrophenyl)-1,3,4-oxadiazol-2-ylthio) -N-(4-(3-(aryl)acryloyl)phenyl)acetamides 5a-n were synthesized via acid-catalyzed aldol condensation (SOCl2) by reacting N-(4-acetylphenyl)-2-(5-(3-nitrophenyl)-1,3,4-oxadiazol-2-ylthio)acetamide (4) with differently substituted aldehydes. Compound (4) was obtained by reacting 5-(3-nitrophenyl)-1,3,4-oxadiazole-2-thiol (2) with N-(4-acetylphenyl)-2- chloroacetamide (3) in the presence of K2CO3. The intermediates (2) and (3) were synthesized simultaneously from 3-nitrobenzohydrazide (1) and 4-aminoacetophenone, respectively. The formation of intermediates and targeted compounds were confirmed for their structure by means of various spectral-analytical techniques like IR, 1H NMR, 13C NMR, elemental analysis, and mass spectra. Antimicrobial properties of all the synthesized compounds have been evaluated against broad panel of bacteria and fungi. Springer Science+Business Media 2013.
- Joshi, Deepkumar,Parikh, Kalpesh Suryakant
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p. 1855 - 1864
(2014/05/06)
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- Synthesis and evaluation of 2-(5-(aryl)-1,3,4-oxadiazol-2-ylthio)-N-(3- (trifluoromethyl)phenyl)acetamides and N-(4-chloro-3-fluorophenyl)-2-(5-(aryl)- 1,3,4-oxadiazol-2-ylthio)acetamides as antimicrobial agents
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A series of 2-mercapto-5-phenyl-1,3,4-oxadiazole derivatives have been condensed with different phenyl acetamide derivatives possessing fluorine atom at meta position; resulting in the formation of 2-(5-aryl-1,3,4-oxadiazol-2- ylthio)-N-(3-(trifluoromethyl)phenyl)acetamide (5a-j) and N-(4-chloro-3- fluorophenyl)-2-(5-aryl-1,3,4-oxadiazol-2-ylthio)acetamide (5k-t) derivatives. The antimicrobial properties of the synthesized entities (5a-t) measured as their MIC (Minimum Inhibitory Concentration) values were evaluated by using the broth dilution method against Gram-positive bacteria (S. aureus and E. faecalis), Gram-negative bacteria (E. coli and P. aeruginosa) and fungi (C. albicans and A. niger). The results of antimicrobial activities (in μg/ml) revealed the fact that the compounds 5a and g bearing a maximum number of fluorine atoms showed the highest potency among the synthesized compounds against the broad panel of bacterial and fungal strains. The presence of fluorine atom at the meta position in the phenyl ring of final derivatives (5a-t) brought about an enhancement of their antimicrobial properties to a notable extent.
- Parikh, Kalpesh,Joshi, Deepkumar
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p. 827 - 835
(2014/07/07)
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- Design, synthesis and biological evaluation of novel arylidine- malononitrile derivatives as non-carboxylic inhibitors of protein tyrosine phosphatase 1B
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In this study, we describe the design, synthesis, biological evaluation and molecular modelling studies of novel non-carboxylic arylidine malononitrile-based molecules as Protein Tyrosine Phosphatase 1B (PTP1B) inhibitors. The synthesized derivatives were evaluated in vitro for glucose reuptake using L6 muscle cell lines and enzymatic assay against PTP1B. The biological activity results showed that the 2-methoxy substituted (14b) compound exhibited significant activity in both the assays. The unsubstituted compound (14a) also possessed comparable activity on glucose reuptake in L6 muscle cell lines and better inhibitory activity on PTP1B enzyme assays. Docking analysis was performed on the most potent compound of the series to understand the nature of interactions governing the binding of the designed molecule with the PTP1B enzyme.
- Deora, Girdhar Singh,Karthikeyan, Chandrabose,Moorthy, N. S. Hari Narayana,Rathore, Vandana,Rawat, Arun K.,Tamrakar, Akhilesh K.,Srivastava,Trivedi, Piyush
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p. 5344 - 5348
(2013/12/04)
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- An expeditious microwave-assisted synthesis of mercapto benzazoles, quinazolinone and oxadiazoles
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A simple, convenient and high yielding synthetic method for the preparation of various mercapto derivatives of benzimidazoles 2a-e, benzoxazole 2f, benzothiazole 2g, quinazolinone 2h, 5- substituted-1,3,4-oxadiazoles 4a-f by the treatment of a series of O, S and N heteroatoms containing bifunctional molecules with potassium isopropyldithiocarbonate under microwave irradiation technique is described.
- Mahesh Kumar,Dubey
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p. 1619 - 1622
(2013/01/15)
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- Synthesis, characterization and evaluation of some 5-substituted 1,3,4-oxadiazole-2-thioesters as antifungal agents
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A series of 5-substituted 1,3,4-oxadiazole-2-thioesters was synthesized by converting several substituted organic acids successively into the corresponding esters, hydrazides and 5-substituted 1,3,4-oxadiazole-2-thiols. Finally the target compounds: 5-substituted 1,3,4-oxadiazole-2-thioesters were obtained by refluxing 5-substituted 1,3,4-oxadiazole-2-thiols in the presence of acid chloride and potassium hydroxide. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The synthesized compounds were evaluated for their in vitro antifungal activity. Some of the evaluated compounds possessed significant antifungal activity as compared to a terbinafine standard.
- Hasan, Aurangzeb,Sheikh, Md Rezaul Karim,Gapil, Shelly
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experimental part
p. 2573 - 2578
(2012/09/07)
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- Synthesis, characterization and antifungal evaluation of 5-substituted-4-amino-1,2,4-triazole-3-thioesters
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A series of 5-substituted-4-amino-1,2,4-triazole-3-thioesters was synthesized by converting variously substituted organic acids successively into the corresponding esters, hydrazides, 5-substituted-1,3,4-oxadiazole-2-thiols, 5-substituted-1,2,4-triazole-2-thiols and 5-substituted-1,3,4-oxadiazole-2- thioesters. Finally the target compounds were obtained by refluxing 5-substituted-1,3,4-oxadiazole-2-thioesters in the presence of hydrazine hydrate and absolute alcohol. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The synthesized compounds were evaluated for their in vitro antifungal activity. Some of the evaluated compounds possessed significant antifungal activity as compared to a terbinafine standard.
- Hasan, Aurangzeb,Thomas, Noel Francis,Gapil, Shelly
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p. 1297 - 1309
(2011/04/24)
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- Synthesis, characterization and antifungal activity of some new 5-substituted 1,3,4-oxadiazole-2-thiols
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A series of 5-substituted 1,3,4-oxadiazol-2-thiols (3a-i) was synthesized by refluxing variably substituted organic acids (Ra-i) with methanol to the corresponding esters (1a-i). These esters were then converted to hydrazides (2a-i) by reaction with hydrazine hydrate in the presence of absolute ethanol which was followed by reaction with carbon disulfide and potassium hydroxide. Structure of the synthesized compounds was established by physicochemical and spectral data analysis. Synthesized compounds were subjected to antifungal activity. Antifungal activity was performed against Aspergillus flavus, Mucor species, Aspergillus niger and Aspergillus fumigates, with test compounds at a concentration of 200 μg/mL. Terbinafine was used as the standard drug.
- Hasan, Aurangzeb,Gapil, Shelly,Khan, Izzat
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p. 2007 - 2010
(2012/02/14)
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- Synthesis, characterization and antifungal activity of some 5-substituted 4-amino-1,2,4-triazole-3-thiols
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A series of 5-substituted 4-amino-1,2,4-triazole-3-thiols (4a-i) was synthesized by refluxing substituted organic acids (a-i) with methanol to the corresponding esters (1a-i). These esters were then converted to hydrazides (2a-i) by reaction with hydrazine hydrate in the presence of absolute ethanol. The hydrazides were then converted to 5-substituted 1,3,4-oxadiazole-2-thiols (3a-i) by cyclization reaction with carbon disulfide and KOH which was followed by reaction with hydrazine hydrate in the presence of absolute ethanol. Structure of the synthesized compounds was established by physico-chemical and spectral data analysis. Synthesized compounds were subjected to antifungal activity. Antifungal activity analysis was performed against Aspergillus flavus, Mucor species, Aspergillus niger and Aspergillus fumigates, with test compounds at a concentration of 200 μg/mL. Terbinafine was used as the standard drug.
- Hasan, Aurangzeb,Akhtar, Mohammad Nadeem,Gapil, Shelly
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p. 5471 - 5476
(2012/07/27)
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- Synthesis and a UV and IR spectral study of some 2-aryl-Δ2-1,3,4-oxadiazoline-5-thiones
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Twenty four 2-aryl-Δ2-1,3,4-oxadiazoline-5-thione derivatives 2 were synthesized and their uv and ir spectra were studied. Correlation between σ-Hammett constants of aryl substituents and the differences in absorption maxima (Δν = ν1-ν2 in kK) of the electronic spectra of the deprotonated species were also evaluated. A new method for the synthesis of the 2-(amino)aryl derivatives 2v,w,x is also reported.
- Charistos,Vagenas,Tzavellas,Tsoleridis,Rodios
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p. 1593 - 1598
(2007/10/02)
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- THE ACIDITIES AND THE TAUTOMERIC STRUCTURE OF 5-ARYL-2-MERCAPTO-1,3,4-OXADIAZOLES
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The acidity constants of a series of substituted 5-phenyl-2-mercapto-1,3,4-oxadiazoles were determined by potentiometric and spectrophotometric methods in 80percent (vol.) ethanol-water at 25 deg C.The data obtained by the two methods are in good agreement.The pKa values correlate with the ?*XC6H4 constants of the substituted phenyl group (p = -0.985, r = 0.936), however, a better correlation of the pKa data with the Hammett substituent constants ?X (p = -0.983, r = 0.959) was obtained.These linear correlations exclude the possibility of the presence of the thiol tautomer 1 in eqiulibrium with the thioamide tautomer 2 and indicate that the ionization of the compounds takes place in the form of the thioamide tautomer 2.According to the results of the HMO calculations, the thioamide form 2 is more stable than the thiol tautomer 1.A satisfactory correlation between the observed pKa values and the difference between the ?-electronic energies (ΔE?) of the thioamide tautomer and of the common resonance-stabilized anion was obtained, thus supporting the assigned tautomeric structure 2 for the series under study.
- Shawali, Ahmad S.,Rizk, Mahmoud S.,Abdelhamid, Abdou O.,Abdalla, Magda A.,Parkanyi, Cyril,Wojciechowska, Magdalena E.
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p. 2211 - 2224
(2007/10/02)
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- Synthesis of Substituted N-(2,4-Dioxo-1,2,3,4-tetrahydroquinazolinyl)benzamides and N-(2-Thiono-4-oxo-1,2,3,4-tetrahydroquinazolinyl)benzamides
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Substuted N-(2,3-dioxo-1,2,3,4-tetrahydroquinazolinyl)benzamides (3a-g) and substituted N-(2-thiono-4-oxo-1,2,3,4-tetrahydroquinazolinyl)benzamides (4a-g) were synthetized in one step from the reaction of methyl anthranilate with 2-aryl-1,3,4-oxadiazolin-5-ones (1a-g) and 2-aryl-1,3,4-oxadiazoline-5-thiones (2a-g), respectively, in m-cresol at 150-160 deg C.Alternative routes leading to the formation of 3a and 4a are also reported.
- Chau, Nguyen,Saegusa, Yasuo,Iwakura, Yoshio
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p. 541 - 544
(2007/10/02)
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