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Öğe Antimicrobial activity of rhodium (I) and ruthenium (II) carbene complexes derived from benzimidazole against staphylococcus aureus isolates(Turkish Journal of Medical Sciences, 1997) Durmaz, Rıza; Küçükbay, Hasan; Çetinkaya, Engin; Çetinkaya, BekirAbstract: As an extension of our previous study, three benzimidazole derivatives and one benzothiazolium salt found to be significantly effective against Staphylococcus aureus (ATCC 29213) were evaluated for their in vitro antimicrobial activity againts 98 Staphylococcus strains isolated from the nasal swabs of hospital staff (68) and clinical specimens (30). The previously snthesized compounds, referred to as 1, 2, 3 and 4, were found to be effective at the average minimal inhibitory concentrations (MICs) of 5.8, 5.5, 18.5 and 15.8 µg/mL, respectively. The resuts of this study show the activity of compounds 1 and 2 against staphylococci to be noteworthy.Öğe Bazı benzimidazol, imidazol ve benzotiyazol türevlerinin in vivo MIC değerleri ile böbrek ve karaciğer fonksiyon testleri ile etkilerinin araştırılması(1997) Durmaz, Rıza; Küçükbay, Hasan; Çetinkaya, Engin; Çetinkaya, Bekir; Günal, SelamiDaha önceki çalışmalarımızda çok sayıda benzimidazol, imidazol ve benzotiyazol türevleri sentez edilerek in vitro şartlarda antimikrobiyal aktiviteleri test edildi. Bileşiklerden dört tanesinin standart ve klinik suşlara karşı minimum inhibitor konsantrayonları (MIC) 5-25 $mu$ g/mL arasında bulundu. En fazla etkili bulunan bu bileşiklerin terapötik amaçla kullanılıp kullanılamayacağına karar verebilmek için serum MIC değerleri ve karaciğer ile böbrek fonksiyonlarına etkileri araştırıldı. In vivo çalışmalarda bir nolu bileşik damar içi, kas içi ve oral yolla; 2, 3 ve 4 nolu bileşikler ise oral ve damar içi yolla farklı konsantrasyonlarda Wistar türü sıçanlara verildi. Madde verildikten 4 ve 24 saat sonra kan alınarak biyoanaliz yöntemiyle serum MIC değerleri ve otoanalizör yardımıyla biyokimyasal parametreler çalışıldı, karaciğer ve böbrekten histolojik inceleme yapıldı. Denemelerin hiç birinde bileşikler serumda MIC değerine ulaşamamıştır. Biyokimyasal parametrelerden kreatinin bütün denemelerde, kan üre azotu seviyeleri ise iki madde ile ilgili bazı denemeler dışında normal, karaciğer fonksiyon testlerinden aspartat aminotransferaz ve/veya alanın aminotransferaz ve/veya alkalen fosfataz değerleri genellikle yüksek bulunmuştur. Elde edilen sonuçlardan, test edilen bileşiklerin karaciğer ve safra yollarında harabiyet oluşturdukları söylenebilir.Öğe Chalcogeno ureas derived from bis(1,3-diazepan-2-ylidene)(Turkish Journal of Chemistry, 2004) Gök, Yetkin; Çetinkaya, EnginAbstract: A series of new electron rich olefins (=CNR(CH2)4NR)2, 3, (a; R = CH2C6H5, b; R = CH2C6H4-OMe-p, c; R = CH2C6H4?NMe2?p) was generated via the condensation of RNH(CH2)4NHR with Me2.NCH(OMe)2. The C=C bond cleavage reactions of 3 with S8 and Se provide a simple and straight-forward method for the synthesis of 1,3-diazepan-2-chalcogenones 4 and 5, respectively.Öğe Effective acyloin condensations catalyzed by electron-rich olefins(Turkish Journal of Chemistry, 1995) Çetinkaya, Engin; Küçükbay, HasanEffective acyloin condensations catalyzed by electron-rich olefins Öz:Öğe In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[$RuCl_2(p-cymene)]_2$ system for transfer hydrogenation reactions(2011) Özcan, Emine Özge; Mercan, Deniz; Gürbüz, Nevin; Çetinkaya, Engin; Çetinkaya, Bekir; Özdemir, İsmailAbstract: Hydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3- dialkyltetrahydropyrimidinium salts (LHX)/[Öğe In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[RuCl_2(p-cymene)]_2 system for transfer hydrogenation reactions(Turkish Journal of Chemistry, 2011) Özcan, Emine Özge; Mercan, Deniz; Gürbüz, Nevin; Çetinkaya, Engin; Çetinkaya, Bekir; Özdemir, İsmailAbstract: Hydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3- dialkyltetrahydropyrimidinium salts (LHX)/[RuCl2(p?cymene)]2 and KOH catalyzed quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol.Öğe Ionic liquids as solvent for efficient esterification of carboxylic acids with alkyl halides(Turkish Journal of Chemistry, 2010) Gök, Yetkin; Alıcı, Bülent; Çetinkaya, Engin; Özdemir, İsmail; Özeroğlu, ÖzlemAbstract: The selective esterification of carboxylic acid derivatives with a variety of alkyl halides was carried out using ionic liquid as solvent in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions (up to 99%) and selectivities. The ionic liquid was recycled and reused.Öğe N-fonksiyonelli tetraaminoalkenler ve türevlerinin , sentezi ve karakterizasyonu(Fırat Üniversitesi Fen ve Mühendislik Bilimleri Dergisi, 2003) Gök, Yetkin; Çetinkaya, EnginThe tetraaminoalkenes which contain -OCH3 (or -OC2H5) on substituents attached to the nitrogen atom were prepared from reaction of 1,3-dialkybenzimidazolidinyum salts with NaH. The reaction of tetraaminoalkenes with S8 and Se were given corresponding 2-substituted benzimidazole derivatives. All compounds were identified by using 1H, 13C?NMR, FT-IR tecniques and micro analysis.Öğe Synthesis and characterization of polyimides prepared from optically active (R,R) and (S,S)-1,3-bis (p-N,N'- dimethylaminobenzyl)-perhydrobenzimidazol-2-thion(Turkish Journal of Chemistry, 2007) Yiğit, Murat; Seçkin, Turgay; Köytepe, Süleyman; Çetinkaya, EnginAbstract: This paper presents the synthesis and characterization of polyimides containing a chiral (R,R)or (S,S) 1,3-bis(p-N,N'-dimethylaminobenzyl)-perhydrobenzimidazol-2-thion unit in the backbone.The reactions occur between equimolar amounts of a dianhydride and an aromatic dimethylamine in the presence of the solvent N-methyl-2-pyrollidone (NMP). In this work, the chiral monomer RR and SS -1,3-bis(p -N,N'-dimethylaminobenzyl)-perhydrobenzimidazol-2-thion were used as diamines. The polyimides obtained were characterized by thermogravimetry (TGA), differential thermal analysis (DTA), differential scanning calorimeter (DSC), infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). It was found that the composition of the polymer had a significant effect upon the thermal behavior of the material.
