Browsing by Author "Tozlu, Israfil"

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Further Derivatives of 4-Benzoyl Acid and Their Antibacterial Activities
(Springer Birkhauser, 2007) Bildirici, Ishak; Sener, Ahmet; Tozlu, Israfil
Compound 4, 5, 6, 7, and 8 were synthesized from 4-benzoyl-1,5-diphenyl-1H-pyrazole- 3-carboxylic acid 1 as a starting material. The pyrazolo[ 4,3-d] oxazinone 4 was obtained from direct reaction of the acid 1 with hydroxylamine hydrochloride. Acid chloride 2 was converted easily into the new derivatives consisting of 1-(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-oyl)-sulfamide 5 and 3,4-dibenzoyl-1,5-diphenyl-1H-pyrazole 6. The nitrile derivative 7 was obtained by dehydration of the amide 3 in a mixture of SOCl2 and Dimethylformamide (DMF). Cyclocondensation reaction of 7 with anhydrous hydrazine led to the formation of 7-aminopyrazolo[ 3,4-d] pyridazine 8 derivative. These new synthesized compounds evaluated for their antibacterial activities against Gram-positive and Gram-negative bacteria using the tube dilution method. The finding of antibacterial activity study showed that the sulfamide derivative 5 was the best compound of the series, exhibiting antibacterial activity against both Gram-positive and Gram-negative bacteria.
Synthesis and Some Reactions of 4-(ethoxycarbonyl) Acid
(Wiley, 2007) Sener, Ahmet; Tozlu, Israfil; Genc, Hasan; Bildirici, Ishak; Arisoy, Kadir
1,5-Diphenyl-1H-pyrazole-3,4-(dicarboxylic acid-4-ethyl ester 2, obtained from the 4-ethoxycarbonyl-5phenyl-2,3-furandione 1 and N-benzylidene-N'-phenyl hydrazine, was converted via reactions of its acid chloride 3 with various alcohols or N-nucleophiles into the corresponding ester 5 or amide derivatives 6, respectively. In addition, 2 was decarboxylated to give ethyl 1,5-diphenylpyrazole-4-carboxylate 4. Nitrile 7 derivative of 2 was also obtained by dehydration of 6a in a mixture of SOCl2 and DMF. While cyclo condensation reaction of 2 with hydrazine hydrate leads to the formation of pyrazolo[3,4d]pyridazine-4,7-dione 8, the reaction of 3 with anhydrous hydrazine provided a new bis pyrazole derivative 9.
Synthesis of Novel Imidazopyridines and Their Biological Evaluation as Potent Anticancer Agents: a Promising Candidate for Glioblastoma
(Pergamon-elsevier Science Ltd, 2018) Guclu, Dilek; Kuzu, Burak; Tozlu, Israfil; Taspinar, Filiz; Canpinar, Hande; Taspinar, Mehmet; Menges, Nurettin
Novel imidazopyridine derivatives were synthesized according to a very simple protocol and then subjected to cytotoxicity testing against LN-405 cells. Two of the compounds exhibited antiproliferative effects on LN-405 cells at 10 and 75 mu M and were selected as lead compounds for further study. Safety experiment for lead compounds on WS1 was carried out and IC50 values were calculated as 480 and 844 mu M. LN-405 cell line were incubated with the lead compounds and then tested for DNA damage by comet assay and effects on cell cycle using flow cytometry. The results of these two tests showed that both lead compounds affected the G0/G1 phase and did not allow the cells to reach the synthesis phase. The log BB (blood-brain barrier) and Caco-2 permeability of the synthesized molecules were calculated and it was shown that imidazopyridine derivatives taken orally are likely to pass through gastrointestinal membrane and the blood-brain barrier.
Synthesis of Novel Tetra-Substituted Pyrazole Derivatives From 2,3-Furandione
(Bentham Science Publ Ltd, 2019) Genc, Hasan; Tasdemir, Volkan; Tozlu, Israfil; Ogun, Erdal
Synthesis of pyrazole-3-carboxylic acid was progressed via two different protocols, one of which is solid state. Pyrazole-3-carboxylic acid was converted into different derivatives such as ester, urea, amide and nitrile. The amide compound was converted to nitrile using SOCl2 and DMF. Solid state heating of carboxylic acid gave decarboxylated product. Cyclization of tetra-substituted pyrazole with hydrazines resulted in pyrazolopyridazinones. The antimicrobial activities of the synthesized pyrazole derivatives against Bacillus cereus, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, and Saccharomyces cerevisiae were evaluated. One of the pyrazole derivatives which possess nitro group showed antimicrobial activity in only B. cereus, a Gram-positive bacteria, with an MIC of 128 mu g/mL.