Bedia Kocyigit-Kaymakcioglu

Synthesis and Biological Activity of Substituted Urea and Thiourea Derivatives Containing 1,2,4-Triazole Moieties

A series of novel thiourea and urea derivatives containing 1,2,4-triazole moieties were synthesized and evaluated for their antifungal and larvicidal activity. Triazole derivatives 3a–e and 4a–e were synthesized by reacting thiocarbohydrazide with thiourea and urea compounds 1a–e and 2a–e, respectively, in a 130–140 °C oil bath. The proposed structures of all the synthesized compounds were confirmed using elemental analysis, UV, IR, 1H-NMR and mass spectroscopy. All compounds were evaluated for antifungal activity against plant pathogens, larvicidal and biting deterrent activity against the mosquito Aedes aegypti L. and in vitro cytotoxicity and anti-inflammatory activity against some human cell lines. Phomopis species were the most sensitive fungi to these compounds. Compounds 1b, 1c, 3a and 4e demonstrated selectively good activity against Phomopis obscurans and only 1b and 4e showed a similar level of activity against P. viticola. Compound 3d, with a LD50 value of 67.9 ppm, followed by 1c (LD50 = 118.8 ppm) and 3e (LD50 = 165.6 ppm), showed the highest toxicity against Aedes aegypti larvae. Four of these compounds showed biting deterrent activity greater than solvent control, with the highest activity being seen for 1c, with a proportion not biting (PNB) value of 0.75, followed by 1e, 2b and 1a. No cytotoxicity was observed against the tested human cancer cell lines. No anti-inflammatory activity was observed against NF-κB dependent transcription induced by phorbol myristate acetate (PMA) in human chondrosarcoma cells.

Biting deterrence and insecticidal activity of hydrazide-hydrazones and their corresponding 3-acetyl-2,5-disubstituted-2,3-dihydro-1,3,4-oxadiazoles against Aedes aegypti.

BACKGROUND Taking into account the improvement in insecticidal activity by the inclusion of fluorine in the hydrazone moiety, the authors synthesized new 4-fluorobenzoic acid hydrazides and 3-acetyl-2,5-disubstituted-2,3-dihydro-1,3,4-oxadiazoles, substituting a phenyl group or a heteroaryl ring carrying one or two atoms of F, Cl and Br, and investigated their biting deterrent and larvicidal activities against Aedes aegypti for the first time. RESULTS The compound 3-acetyl-5-(4-fluorophenyl)-2-[4-(dimethylamino)phenyl]-2,3-dihydro-1,3,4-oxadiazole (17) produced the highest biting deterrent activity (BDI = 1.025) against Ae. Aegypti, followed by 4-fluorobenzoic acid [(phenyl)methylene] hydrazide (1). These activity results were similar to those of N,N-diethyl-meta-toluamide (DEET), which showed a proportion not biting of 0.8-0.92. When compounds 1 and 17 were tested on cloth worn on human volunteers, compound 1 was not repellent for some volunteers until present in excess of 500 nmol cm(-2) , while compound 17 was not repellent at the highest concentration tested (1685 nmol cm(-2) ). In the larvicidal screening bioassays, only compounds 10, 11, 12 and 17 showed 100% mortality at the highest screening dose of 100 ppm against Ae. aegypti larvae. Compounds 11 and 12 with LD50 values of 24.1 and 30.9 ppm showed significantly higher mortality than 10 (80.3 ppm) and 17 (58.7 ppm) at 24-h post-treatment. CONCLUSION The insecticidal and biting deterrent activities were correlated with the presence of a halogen atom on the phenyl or heteroaryl substituent of the hydrazone moiety.

Anticonvulsant activity of 3,5-dimethylpyrazole derivatives in animal models

A series of 3,5-dimethylpyrazole derivatives, structurally related to the previously described potent ameltolide analogues, were synthesized and evaluated for their anticonvulsant activity. Ten compounds were prepared by reacting the 4-amino-3,5-dimethylpyrazole with appropriate substituted carboxylic acids, benzoyl chlorides and benzaldehydes to obtain amide and imine derivatives. Initial anticonvulsant screening was performed using intraperitoneal pentylenetetrazole (PTZ) and maximal electroshock (MES) induced seizure tests in mice. Among the 10 tested compounds, N-[1-(4-methoxybenzoyl)-3,5-dimethylpyrazole-4-yl]-4-methoxybenzamide 2 and N-[1-(2,6-dichlorobenzoyl)-3,5-dimethylpyrazole-4-yl]-2,6-dichlorobenzamide 3 decreased seizure severity and the mortality rate in the PTZ test. Hence, compound 3 was tested in an animal model of absence epilepsy, Genetic Absence Epileptic Rats from Strasbourg (GAERS). There were no significant changes in the duration or number of spike-and-wave discharges in this model.

Synthesis and anticonvulsant activity of new N-(alkyl/sub-stituted aryl)-N'-[4-(5-cyclohexylamino)-1,3,4-thiadiazole-2-yl)phenyl]thioureas.

A series of novel thiourea derivatives carrying the 5‐cylohexylamino‐1,3,4‐thiadiazole moiety was synthesized and their anticonvulsant activity was evaluated. Structures of the synthesized compounds have been confirmed by IR, 1H‐NMR, and elemental analysis. All of the compounds were administered at a dose of 50 mg/kg. Some of the active compounds have different effects in pentylenetetrazole (PTZ) and maximal electroshock (MES) tests, indicating the therapeutical potential in petit mal seizures, but not in grand mal seizures. Compounds 10, 11, 13, and 14 carrying 2‐methylphenyl, 4‐chlorophenyl, allyl, and 4‐methylphenyl on the thiourea pharmacophore, increased the survival rate in the PTZ model. The ED50 values of the active compounds 10, 11, 13, and 14 were found 68.42, 43.75, 18.75 and 25 mg/kg, respectively.

Synthesis and antinociceptive-antimicrobial activities of some new amide derivatives of 3,5-di/-and 1,3,5-trimethylpyrazoles

Some N-(3,5-di-/1,3,5-trimethylpyrazole-4-yl)-4-substitutedbenzamide derivatives were prepared as possible antiociceptive-antimicrobial agents. New amide derivatives (3–12) were synthesized by reacting 4-amino-3,5-di and 1,3,5-trimethylpyrazoles with 4-substitutedbenzoyl chlorides. Hotplate and tail-immersion tests were used for the determination of the antinociceptive activity. Morphine, was used as a standard test drug. All compounds were administered at a dose of 100 mg/kg ip and some of them had significant antinociceptive activity in both tests. Compound 10 (N-(1,3,5-trimethylpyrazole-4-yl)-4-bromobenzamide), was the most active one in both tests among the compounds. The antinociceptive activity of the compounds 10, 11 (N-(1,3,5-trimethylpyrazole-4-yl)-4-chlorobenzamide), and 12 (N-(1,3,5-trimethylpyrazole-4-yl)-4-fluorobenzamide), started at 30 minutes and continued up to 150 minutes in the hotplate test. Also compounds were tested for their in vitro antimicrobial activity, but exhibited weak antibacterial activity.

High pressure liquid chromatographic analysis ofin vivo metabolites ofN(substituted phenyl)-N′-(1,3,5-trimethyl pyrazole-4-yl)thioureas in rats

SummaryThe aim of this study was to investigate the in vivo metabolism ofN-(substituted phenyl)-N-( 1,3,5-trimethylpyrazole-4-yl)thioureas (substrate) as model compounds in rats via HPLC. The substrates,N-(4-fluoro/chlorophenyl)-N’-(1,3,5-trimethylpyrazole-4-yl)thioureas (T2 and73), and their possible metabolites were synthesized and the structures of the compounds were elucidated both by spectral and elemental analysis. Substrates were dissolved in 5% gum arabic and administered 100 mg/kg intraperitoneally (i.p.) in a volume of 0.1 ml/100 g. Blood samples were withdrawn before and at 30 min, 1, 2, 4, 8, 12 and 24 h post-dose. Chromatographic separation of the substrate and its metabolites was performed using a Hichrom chromasil C18 column (150 mmx4.6 mm i.d., 5 μm particle size). The optimal composition of the mobile phase was achieved by using different mixtures of pure methanol and water. From the biotransformation of these thiourea compounds,N-dealkylation metabolitesN (4-fluoro/chloro-phenyl)-N’-(3,5-dimethylpyrazole-4-yl)thioureas (T1 andT4) were identified together with unchanged substrate (T2 andT3) in the plasma by comparing them to reference standards via HPLC UV/DAD.

Synthesis and structure–activity relationships of carbohydrazides and 1,3,4-oxadiazole derivatives bearing an imidazolidine moiety against the yellow fever and dengue vector, Aedes aegypti

BACKGROUND 1,3,4-Oxadiazole and imidazolidine rings are important heterocyclic compounds exhibiting a variety of biological activities. In this study, novel compounds with oxadiazole and imidazolidine rings were synthesized from 3-(methylsulfonyl)-2-oxoimidazolidine-1-carbonyl chloride and screened for insecticidal activities. The proposed structures of the 17 synthesized compounds were confirmed using elemental analysis, infrared (IR), proton nuclear magnetic resonance (1 H-NMR), and mass spectroscopy. RESULTS None of the compounds showed larvicidal activity at the tested concentrations against first-instar Aedes aegypti larvae. However, nine compounds exhibited promising adulticidal activity, with mortality rates of ≥80% at 5 µg per mosquito. Further dose-response bioassays were undertaken to determine median lethal dose (LD50 ) values. Compounds 1, 2b, 2c, 2d, 2 g, 3b, 3c, 3 g, and 3 h were effective, with typical LD50 values of about 5 - 10 µg per mosquito against female Ae. aegypti. Compounds 2c (bearing a nitro group on the aromatic ring; LD50 = 2.80 ± 0.54 µg per mosquito) and 3 h (double halogen groups at 2,4 position on the phenyl ring; LD50 = 2.80 ± 0.54 µg per mosquito) were the most promising compounds. CONCLUSION Preliminary mode of action studies failed to show consistent evidence of either neurotoxic or mitochondria-directed effects. Further chemical synthesis within this series may lead to the development of new effective insecticides.

Design, synthesis and evaluation of biological activities of some new carbohydrazide and urea derivatives

Objectives: Urea and carbohydrazide derivatives are important compounds exhibiting cytotoxic activities. In this study, a series of new urea and carbohydrazide derivatives containing an pyridine ring were synthesized and evaluated for cytotoxic activity. Materials and Methods: The proposed structures of the synthesized compounds were confirmed using elemental analysis, IR, and 1H-NMR spectroscopic techniques. The cytotoxic potencies of synthesized compounds were determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT) on BRCA mutant-carrying HCC1937 and Capan-1 cell lines, as well as on MCF7, HeLa, and MRC5 cells. Results: 3a, 3b, 3c and 3d showed cytotoxic activity against all cancer cell lines. Conclusion: Our data indicate that compounds 3a-d are more selective to cancer cells compared with nontumoral fibroblasts; however, these compounds are not more potent on HR defective cells with BRCA mutants.

Synthesis, anticancer activity and ADMET studies of N-(5-methyl-1,3,4-thiadiazol-2-yl)-4-[(3-substituted)ureido/thioureido] benzenesulfonamide derivatives

GRAPHICAL ABSTRACT ABSTRACT A series of novel 4-[(3-substituted)ureido]-N-(5-methyl-1,3,4-thiadiazol-2-yl) benzenesulfonamides and 4-[(3-substituted)thioureido]-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamides were prepared from 4-amino-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide (sulfamethizole). The structures of the synthesized compounds were determined by IR, 1H-NMR, MS and elemental analysis. The anticancer activity of these compounds was evaluated against human colorectal carcinoma (HCT116) and human cervix carcinoma (HeLa) cell lines. Compound 4 (4-{[(2,4-dichlorophenyl)carbamoyl]amino}-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide) showed marked anticancer activity, being the most active compounds in this series with the IC50 value of 13.92 ± 0.22 µM and 37.91 ± 0.10 µM against HeLa and HCT116, respectively. In silico, ADMET was used to examine their pharmacokinetic properties. ADMET (absorption, distribution, metabolism, excretion, and toxicity) studies were applied to develop new anticancer compound(s) with high selectivity.

Design and evaluation of biological activities of 1,3-oxazolidinone derivatives bearing amide, sulfonamide, and thiourea moieties

1,3‐Oxazolidine‐2‐one is an important heterocyclic ring participating in the chemical structure of many drugs. In this research, 22 new amide/sulfonamide/thiourea derivatives (1–22) were obtained by the reaction of (S)‐4‐(4‐aminobenzyl)‐2(1H)‐1,3‐oxazolidinone with 4‐substituted benzoyl chlorides, 4‐substituted benzene sulfonyl chlorides, and 4‐substituted phenyl isothiocyanates. The structures of all synthesized compounds were clarified by FT‐IR, NMR, and mass spectroscopic and elemental analysis techniques. The synthesized compounds were screened for their antimicrobial activity. Antimicrobial susceptibility and cellular physiology were evaluated using the microbroth dilution assay and the flow cytometry method. As a result, it was determined that compound 16 displayed better antimicrobial activity than chloramphenicol against Gram‐positive bacteria, especially Staphylococcus aureus. In order to understand the mechanism of effect of the compounds on the cell membrane, fluorescence microscopy was used. Cell membrane damage of the Gram positive bacteria treated with compound 16 was observed as a result of intense staining with propidium iodide. In addition, genotoxicity, cytotoxicity, and absorption, distribution, metabolism, and excretion (ADME) parameters of compound 16 were examined and it was found as non‐mutagenic and non‐cytotoxic at the concentration at which it showed antimicrobial activity. According to the calculated ADME parameters and drug likeness scores, the compounds can be good drug candidates, especially compound 16.