Bahittin Kahveci

Synthesis of 4-Amino-4,5-dihydro-1H-1,2,4-triazole-5-ones and their Isatin-3-imine Derivatives

Iminoester hydrochlorides 1 have been synthesized. These compounds were then converted into ester ethoxycarbonyl hydrazones 2, from which in turn a new series of substituted 4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones, 3, was then prepared. Finally a set of isatin imine derivatives 4 was obtained from the reaction of compounds 3 with isatin. The structures of all the new synthesized compounds were confirmed by elemental analyses, IR, 1H-NMR and 13C-NMR spectra.

Microwave-assisted synthesis of new benzimidazole derivatives with lipase inhibition activity

Abstract A practical protocol has been used for the synthesis of benzimidazoles. The reaction of iminoester hydrochlorides of phenylacetic with 4,5-dichloro-1,2-phenylenediamine under microwave irradiation leads to the benzimidazole derivatives with good yields and in short reaction times. After the synthesis of benzimidazoles, we synthesized ester and hydrazide derivatives under microwave irradiation with good yields. All compounds were evaluated with regard to pancreatic lipase activity and 3b, 3c, 5a and 6a showed lipase inhibition at various concentrations.

Microwave-Assisted Synthesis and Biological Evaluation of Some Benzimidazole Derivatives Containing a 1,2,4-Triazol Ring

A new series of 2‐(4‐(trifluoromethyl)phenyl)‐1H‐benzo[d]imidazole derivatives containing a 1,2,4‐triazole ring were synthesized via microwave technique. This efficient procedure provides pure products within a few minutes. The newly synthesized compounds were confirmed by 1H NMR and 13C NMR spectra and they were screened for their lipase inhibition and antioxidant activities. Compounds 4a, 4b, 5a, and 5b showed very good scavenging activity.

Rapid synthesis and lipase inhibition activity of some new benzimidazole and perimidine derivatives

This study presents a synthesis of new series of some benzimidazole, bisbenzimidazole and perimidine derivatives via microwave technique, which, leads to the good product yields and short reaction times. The structure of newly synthesized compounds was confirmed by 1H NMR and 13C NMR spectra. These compounds were screened for their lipase inhibition activity. Then, all compounds were evaluated with regard to pancreatic lipase activity, and some of the 2-substituted perimidines, bisperimidine and bisbenzimidazole derivatives showed lipase inhibition at various concentrations.

Synthesis of Some Novel 1,2,4‐Triazol‐3‐one Derivatives Bearing the Salicyl Moiety and Their Anticonvulsant Activities

A series of new 1,2,4‐triazole‐3‐one derivatives bearing the salicyl moiety were synthesized by using microwave irradiation, and their chemical structures were identified by IR, 1H NMR, 13C NMR, elemental analysis, and LC‐MS. The anticonvulsant activities of the compounds 4a–c, 4e, and 5a–e were evaluated by the Anticonvulsant Screening Program of the National Institute of Health, USA. The compounds had moderate anticonvulsant activities in the maximum electroshock‐induced seizure and minimal clonic seizure models in mice, without any neurotoxic effects.

Synthesis and antioxidant activities of some new triheterocyclic compounds containing benzimidazole, thiophene, and 1,2,4-triazole rings

Abstract Various triheterocyclic compounds containing benzimidazole, thiophene, and 1,2,4-triazole rings (3–6) were synthesized and screened for their antioxidant activities. The structures of the synthesized compounds (2–6) were judged by 1H NMR, 13C NMR, elemental analysis, and LC-MS spectral data. Antioxidant activities of the synthesized compounds (2–6) were determined with CUPric Reducing Antioxidant Capacity (CUPRAC), ABTS (2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/persulfate, and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays. Most of the compounds showed a significant antioxidant activity and especially, compound 5c showed very good SC50 value for DPPH method and compound 5h exhibited very high scavenging activity to ABTS method.

Effect of microwave irradiation on the synthesis of 1,2,4-triazol-3-one derivatives and their antimicrobial activities

An easy efficient method for the synthesis of N-(3,5-dichlorophenyl)-5-alkyl/aryl-3H-1,2,4-triazol-3-one derivatives under microwave irradiation has been developed using the reaction of 3,5-dichloroaniline and ethoxycarbonylhydrazones. This reaction occurs more efficiently and faster than the conventional heating method. We obtained 5-mercapto-1,3,4-oxadiazol derivatives by this method. The newly synthesised compounds have been tested for their antimicrobial activity against Enterobacter cloaceae, Escherichia coli, Klebsiella pneumonie, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhimurium, Yersinia pseudotuberculosis, Bacillus subtilis and Staphylococcus aereus.

Synthesis and Study of α-Glucosidase Inhibitory, Antimicrobial and Antioxidant Activities of Some Benzimidazole Derivatives Containing Triazole, Thiadiazole, Oxadiazole, and Morpholine Rings

A new series of 2-(4-bromobenzyl)- and 2-(4-fluorobenzyl)-1H-benzimidazole derivatives containing 1,2,4-triazole, 1,3,4-thiadiazole, 1,3,4-oxadiazole, and morpholine rings has been synthesized. The structures of the newly synthesized compounds were confirmed by 1H and 13C NMR and mass spectra, and all substances have been screened for their α-glucosidase inhibitory, antimicrobial and antioxidant activities. Hydrazide, oxadiazole, thiosemicarbazide, and 1,2,4-triazole-3-thiol derivatives showed very good ABTS scavenging activities (IC50 1.94-4.79 μM). Oxadiazole and thiosemicarbazide derivatives also revealed notable DPPH scavenging activity. 5-[(2-(4-Bromobenzyl)-1H-benzimidazol-1-yl)methyl]-1,3,4-oxadiazole-2-thiol was found to be more potent than acarbose. 2-(4-Fluorobenzyl)-1H-benz- imidazole was effective against both Gram-positive and Gram-negative bacteria, especially, M. smegmatis.

Synthesis and molecular docking study of some 5,6-dichloro-2-cyclopropyl-1H-benzimidazole derivatives bearing triazole, oxadiazole, and imine functionalities as potent inhibitors of urease

A new series of benzimidazole compounds including hydrazinecarbothioamide, 1,2,4-triazole, 1,3,4-oxadiazole and imine function were synthesized starting from 5,6-dichloro-2-cyclopropyl-1H-benzimidazole. All of the benzimidazole derivatives exhibited good urease inhibitor activity. Compound 6a proved to be the most potent showing an enzyme inhibitory activity with an IC50=0.06µM. Molecular docking studies were also conducted on enzyme extracted from Jack bean urease to identify the binding mode of the newly synthesized compounds.

Microwave-promoted synthesis and biological activity of some 2-hetarylmethyl-4-(4-hetarylphenyl)-5-methyl-2,4-dihydro-3 H -1,2,4-triazol-3-one derivatives

A series of fused and non-fused 1,2,4-triazole derivatives were prepared starting from ethyl 4-[1-(2-ethoxy-2-oxoethyl)-3-methyl-5-oxo-1,5-dihydro-4H-1,2,4-triazol-4-yl]benzoate. Firstly, both ethyl ester groups were simultaneously transformed into hydrazide groups, then into 4-amino-5-mercapto-4H-1,2,4-triazol-3-yl groups using both microwave-assisted and conventional methods. The latter products interacted with 2 equiv of phenacyl bromides, chloroacetone, or chloroacetic acid to form ring assemblies containing two [1,2,4]triazolo-[3,4-b][1,3,4]thiadiazine fragments. Cyclization using 2 equiv of carboxylic acids, urea, or CS2 leads to the corresponding [1,2,4]triazolo-[3,4-b][1,3,4]thiadiazole derivatives. The synthesized compounds were evaluated in regard to their antimicrobial, anti-lipase, and antiurease activities.