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1,4,5,6-tetrahyropyrimidinium halides ligands for Suzuki-Miyaura cross-coupling of unactivated aryl chlorides
(Pergamon-Elsevier Science Ltd, 2005) Alici, B; Özdemir, I; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
Four functionalized bis(1,4,5,6-tetrahyropyrimidinium) salts (2a-d) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle and environmentally benign process for palladium mediated Suzuki cross-coupling was developed. The in situ prepared three component system Pd(OAC)(2) / bis(1,4,5,6-tetrahyropyrimidinium) bromides (2a-d) and CS2CO3 catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride.
Benzimidazolin-2-ylidene-palladium-catalysed coupling reactions of aryl halides
(Wiley, 2005) Gök, Y; Gürbüz, N; Özdemir, I; Çetinkaya, B; Çetinkaya, E
The in situ prepared three-component system Pd(OAC)(2)-1,3-dialkylbenzimidazolium chlorides (2a-f) and CS2CO3 catalyses, quantitatively, the Suzuki cross-coupling of deactivated aryl chlorides and Heck coupling reactions of aryl bromide and iodide substrates. The 1,3-dialkylbenzimidazolium salts (2a-f) were characterized by conventional spectroscopic methods and elemental analysis. Copyright (c) 2005 John Wiley & Sons, Ltd.
Effects of caffeic acid phenethyl ester and epidermal growth factor on the development of caustic esophageal stricture in rats
(W B Saunders Co, 2001) Koltuksuz, U; Mutus, HM; Kutlu, R; Özyurt, H; Çetin, S; Karaman, A; Gürbüz, N
Background/Purpose: An experimental study was performed to modify the healing response in caustic esophageal burns to prevent stricture development. Two different agents with different modes of actions, caffeic acid phenethyl ester (CAPE) and epidermal growth factor (EGF), were studied. CAPE has antiinflammatory, immunomodulatory, antioxidant, and antimitotic properties. EGF has known properties in supporting wound healing and in protecting esophagus from injuries. Methods: The model described by Gehanno and its modification by Liu was used to create standard esophageal burns with 50% NaOH. The study was performed with 76 rats in 4 main groups (sham, CAPE, EGF, and control) and 2 subgroups in each for 5 and 28 days of observation. Efficacy of treatment was assessed in 28-day subgroups by measuring weight gain, contrast esophagograms on day 27, histologic evaluation by measuring stenosis index (wall thickness/lumen diameter), and collagen deposition, and biochemically by determining tissue hydroxy proline (OHP) content. Results: In the end of the study, increase rates of mean body weights of the animals in the 28-day subgroups were as follows: sham, 30%; CAPE, 23%; EGF, 22%; and control, 14%. Although all the animals in subgroups significantly gained weight, the mean weight gain was significantly low in controls when compared with sham, CAPE, and EGF groups (P < .05). Contrast esophagograms on day 27 showed no stenosis in the sham, mild stenosis in CAPE and EGF, and severe stenosis with proximal dilatation in controls. Stenosis indices of the subgroups were as follows: sham, 0.29; CAPE, 0.41; EGF, 0.41; control, 0.84. Index was significantly higher in controls (P < .05). Collagen accumulation scores in the esophageal wall were as follows: Sham, 0.0; CAPE, 0.87; EGF, 0.30; control, 2.70. Scores also were significantly higher in controls (P < .05). Tissue (OHP) levels were as follows (mg/g dry tissue): Sham, 1.48; CAPE, 1.53; EGF, 1.90; control, 4.01. Production of OHP was significantly higher in controls. Conclusions: The results of the parameters in the study indicate that administration of CAPE and EGF has beneficial effects in the prevention of caustic esophageal strictures. Those effects of CAPE may occur through its antiinflammatory, immunomodulatory, and antioxidant properties, and EGF may occur through its induced proliferative properties on the esophagus. Copyright (C) 2001 by WB. Saunders Company.
Improved palladium-catalyzed coupling reactions of aryl halides using saturated N-heterocarbene ligands
(Elsevier Science Bv, 2004) Gürbüz, N; Özdemir, I; Demir, S; Çetinkaya, B
The incorporation of saturated N-heterocyclic carbenes into palladium pre-catalysts gives high catalyst activity in the Suzuki coupling of aryl iodides, bromides and deactivated aryl chloride substrates, whereas the yield of the palladium catalyzed Heck reaction of deactivated aryl chlorides is negligible. The complexes were generated in the presence of Pd(OAc)(2) by in situ deprotonation of 1,3-dialkylimidazolinium salts LHX (1) which were characterized by conventional spectroscopic methods and elemental analyses. (C) 2003 Elsevier B.V. All rights reserved.
In situ generated palladium catalysts bearing 1,3-dialkylperimidin-2-yline ligands for Suzuki reactions of aryl chlorides
(Elsevier, 2004) Özdemir, I; Alici, B; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
Four new 1,3-dialkylperimidinium halides have been prepared and characterized. The in situ prepared three component system Pd(OAc)(2)/1,3-dialkylperimidinium (1a-d) and Cs2CO3 catalyses the Suzuki cross-coupling of deactivated aryl chloride substrates in excellent yields under mild conditions. (C) 2004 Elsevier B.V. All rights reserved.
In situ preparation of palladium N-heterocyclic carbene complexes and use for Suzuki reaction
(Wiley, 2005) Özdemir, I; Gök, Y; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
The in situ prepared three component system Pd(OAc)(2), 1,3-dialkylbenzimidazolium halides (1a-e) and t-BuOK catalyses quantitatively the Suzuki cross-coupling of deactivated aryl chloride substrates. 1,3-Dialkylbenzimidazolium salts (1a-e) were characterized by conventional spectroscopic methods and elemental analyses.
In-situ generated 1-alkylimidazoline-palladium catalyst for the Suzuki cross-coupling reaction of aryl chlorides
(Taylor & Francis Inc, 2005) Özdemir, I; Sahin, N; Gürbüz, N; Demir, S; Gök, Y; Çetinkaya, B; Getinkaya, E
Five 1-alkyimidazoline (1-5) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. New in situ generated palladium-imidazoline complexes were tested for catalytic activity in the Suzuki coupling reaction between phenylboronic acid and several aryl chlorides.
In-situ generated functionalized benzimidazol-2-ylidene-palladium catalyst for Suzuki reaction
(Polish Chemical Soc, 2004) Özdemir, I; Gök, Y; Gürbüz, N; Yasar, S; Çetinkaya, E; Çetinkaya, B
From readily available starting materials functionalized 1,3-dialkylbenzimidazolium salts (la-g) have been prepared and characterized by conventional spectroscopic methods and elemental analysis. The in situ prepared three component system Pd(OAC)(2)/1,3-dialkylbenzimidazolium halides (1a-g) and Cs2CO3 catalyses Suzuki cross-coupling of aryl chloride substrates. These concepts for making catalysts in situ open the way for the discovery of many new catalysts via the interaction of commercially available metal complexes and suitable electron releasing ligands.
Interferon-alpha reduces the development of experimental necrotizing enterocolitis
(Academic Press Ltd- Elsevier Science Ltd, 2004) Uguralp, S; Mizrak, B; Karabulut, AB; Gürbüz, N; Demircan, M
Cytokines had important role in the pathogenesis of necrotizing enterocolitis (NEC). The aim of this study is to investigate if IFN-alpha has a prophylaxic, effect on experimental NEC development in newborn rat pups. Twenty eight Wistar Albino newborn rat pups were divided into three groups. Control group rats were breast-fed, NEC group and interferon (IFN) group rat pups were hand-fed with premature newborn formula. IFN-alpha was administered subcutaneously at a dose of 50,000 IU/rat/day in IFN group. NEC was induced experimentally by cold stress twice a day in IFN and NEC groups. On the fourth day, the rats were killed, and all the intestine were removed to determine the tissue level of malonaldehyde (MDA) and histologic changes. The microscopic lesions in the NEC group rats were virtually the same as those seen in neonatal NEC, with severe separation of submucosa and/or lamina propria, loss of villi and in some cases necrosis to extention the muscularis. In contrast, in the rats treated with IFN, lesions were moderate separation of submucosa and/or lamina propria, edema in submucosal and muscular layers. Intestinal injury score and MDA levels in NEC group were significantly higher than in the IFN group (P < 0.05). In conclusion it was suggested that IFN-a was effective in reducing the severity of NEC in rat pups. (C) 2004 Elsevier Ltd. All rights reserved.
Palladium-catalyzed Suzuki reaction using 1,3-dialkylbenzimidazol-2-ylidene ligands in aqueous media
(Wiley-Hindawi, 2004) Özdemir, I; Gök, Y; Gürbüz, N; Çetinkaya, E; Çetinkaya, B
From readily available starting compounds, six functionalized 1,3-dialkylbenzimidazolium salts (2a-c and 4a-c) have been prepared and characterized by conventional spectroscopic methods and elemental analyses. A highly effective, easy to handle, and environmentally benign process for palladium-mediated Suzuki cross-coupling was developed. The in situ prepared three-component systems Pd(OAc)(2)/1,3-dialkylbenzimidazolium chlorides and Cs2CO3 catalyze quantitatively the Suzuki cross-coupling of deactivated aryl chlorides. (C) 2004 Wiley Periodicals, Inc.
Palladium-catalyzed Suzuki-Miyaura reaction of aryl chlorides in aqueous media using tetrahydrodiazepinium salts as carbene ligands
(Georg Thieme Verlag Kg, 2005) Özdemir, I; Gürbüz, N; Gök, Y; Çetinkaya, E; Çetinkaya, B
A highly effective, easy to handle, and environmentally benign process for palladium-mediated Suzuki cross-coupling was developed. The in situ prepared three-component system of Pd(OAc)(2), 1,3-dialkyltetrahydrodiazepinium chlorides (2a-e), and K2CO3 catalyzes quantitatively the Suzuki-Miyaura cross-coupling of deactivated aryl chloride.
Palladium-catalyzed Suzuki-Miyaura reaction using saturated N-heterocarbene ligands
(Springer, 2004) Özdemir, I; Çetinkaya, B; Demir, S; Gürbüz, N
The incorporation of saturated N-heterocyclic carbenes into palladium pre-catalysts give high catalyst activity in the Suzuki coupling of deactivated aryl chloride substrates. [GRS] The complexes were generated in the presence of Pd(OAc)(2) by in situ deprotonation of bis(imidazolinium) bromides LHX (3) which were characterized by conventional spectroscopic methods and elemental analyses.
Polyimides from a novel monomer 3,6-bis(dimethylamino) acridine(p-cymene)dichlororuthenium(II) for a catalytic application
(Springer, 2004) Seckin, T; Koytepe, S; Özdemir, I; Gürbüz, N; Çetinkaya, B
Tricyclic heteroaraomatic dye-based monomer containing NMe2 units, 6-bis(dimethylamino)acridine(p-cymene)dichlororuthenium (II), was used to prepare novel polyimides via a one-stage solution polycondensation due to their stability under a variety of oxidative and reductive conditions. The Ru(II) complex monomer was synthesized starting from [RuCl2(p-cymene)](2) and 3,6-bis(dimethylamino)acridine. A series of stable polyimides was synthesized from the Ru(II) complex of 3,6-bis(dimethylamino)acridine and various aromatic dianhyrides. The polymers had inherent viscosities ranging from 1.72 to 2.11 dL/g and were soluble in polar solvents. The glass transition temperatures were 192-278degreesC, and the 10% weight loss temperatures were above 503-635degreesC. Ruthenium-substituted polyimides were tested for catalytic activity in the furan formation reaction of (Z)-3-methylpent-2-en-4-yn-1-ol. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-1-ol without a solvent and the pure furan was isolated by distillation under reduced pressure. The conversion of the starting, enynol, was determined by gas chromatography (GC).
Protective effect of polyunsaturated phosphatidylcholine on liver damage induced by biliary obstruction in rats
(W B Saunders Co-Elsevier Inc, 2003) Karaman, A; Demirbilek, S; Sezgin, N; Gürbüz, N; Gürses, I
Background/Purpose: Persistent inflammatory response secondary to congenital or acquired biliary choleastasis plays an important role in the pathophysiology of hepatic tissue damage. The polyunsaturated fatty acids (PUFA) have been shown to suppress the inflammatory reactions in vivo and in vitro. PUFA has been shown also to protect againts various types of experimental liver damage in animal models and isolated hepatocytes. Therefore, the aim of this study was to investigate the protective effect of PUFA administration on liver damage using the rat chronic biliary obstruction model. Methods: Swiss albino rats of either sex were divided into 4 groups as follows: control group (group 1, 10 rats); rats with sham operation and treated with saline group 2, 10 rats); rats with biliary obstruction (group 3, 15 rats); and polyunsaturated phophatidylcholine (PPC)-treated rats with biliary obstruction (Group 4, 15 rats). Biliary obstruction was induced by double ligation and division of the common bile duct. PUFA treatment was started 2 weeks later from biliary obstruction in doses of 50 mg/d per rat and continued for 2 weeks. All animals were killed after 4 weeks of common bile duct ligation or sham operation. Liver damage and cholestasis were determined by biochemical and histologic examinations. Results: The data showed a decrease in plasma bilirubin level (both conjugated and unconjugated) and liver enzyme levels (AST, ALT, AP, GGT, 5'-NT) in group 4, when compared with group 3 (P < .05). Tissue levels of malondialdehyde (MDA) in group 4 was 20.00 +/- 2.93 compared with that in group 3, 27.12 +/- 2.96 (P < .05). Administration of PUFA to the biliary obstructed rats resulted in inhibition of collagen accumulation (P < .05) and ductal proliferation (P < .05). Conclusions: PUFA reduced liver damage, ductular proliferation, and fibrosis in biliary obstructed rats. These effects suggest that it might be a useful agent to preserve liver function in patients with biliary obstruction such as biliary atresia. (C) 2003 Elsevier Inc. All rights reserved.
Protective effect of polyunsaturated phosphatidylcholine pretreatment on stress ulcer formation in rats
(W B Saunders Co-Elsevier Inc, 2004) Demirbilek, S; Gürses, I; Sezgin, N; Karaman, A; Gürbüz, N
Purpose: The aim of this study was to investigate whether polyunsaturated phosphatidylcholine. (PPC) pretreatment has any protective effect on gastric mucosal damage induced by cold-restraint stress (CRS) in rats. Methods: Forty swiss albino rats were divided into 3 groups. Group 1 (n = 10) was control, group 2 (n = 15) was stress ulcer, and group 3 (n = 15) was PPC-treated rats with stress ulcer. Stress ulcer was induced by the cold-restraint method for 4 hours at 4degreesC after a starvation period of 72 hours. In the group 3 rats, PPC treatment was started 10 days before stress at a dose of 100 mg/d by oral route. Rats were terminated, stomachs were excised. Macroscopic ulcer index (UI), gastric tissue malondialdehyde (MDA) and superoxide dismutase (SOD) activities, plasma total nitrite, and erythrocyte catalase (CAT) concentrations were assayed. Results: Histopathologic examination showed a stress ulcer index of 0.12 +/- 0.19 mm in the treatment group and 23.6 +/- 8.97 mm in the stress ulcer group (P < .001). Tissue MDA and SOD concentrations were higher in the stress ulcer group than in the treatment group, the differences were statistically significant (P < .001). Plasma NO3- + NO2- levels were higher (P < .005) and CAT levels were lower (P < .001) in the nontreatment group. There were no significant differences with respect to UI, MDA, and SOD levels among the control and treatment groups (P > .05). Conclusions: These results suggest that pretreating rats with PPC inhibits cold-restraint stress-induced gastric mucosal injury and might be useful in preventing stress-induced stomach ulcers. (C) 2004 Elsevier Inc. All rights reserved.
Regioselective allylic alkylation and etherification catalyzed by in situ generated N-heterocyclic carbene ruthenium complexes
(Pergamon-Elsevier Science Ltd, 2006) Gürbüz, N; Özdemir, I; Çetinkaya, B; Renaud, JL; Demerseman, B; Bruneau, C
Benzimidazolium halides are used for the first time as ligand precursors in ruthenium-catalyzed substitution of allylic carbonates and chlorides by carbon nucleophiles and phenols, respectively. After generation of diaminocarbene species upon deprotonation by tBuOK, their association with [Cp*Ru(MeCN)(3)]PF6 induces a very high regioselectivity in favor of the branched isomers when cinnamyl derivatives are used as starting substrates. They also provide good regioselectivities for the allylation of phenols by unsymmetrical aliphatic allylic substrates such as 3-chloro-4-phenylbut-1-ene, and thus provide a straightforward access to new allylic phenyl ethers. (c) 2005 Elsevier Ltd. All rights reserved.
Rhodium-benzimidazolidin-2-ylidene catalyzed addition of arylboronic acids to aldehydes
(Springer, 2005) Özdemir, I; Gürbüz, N; Gök, Y; Çetinkaya, B; Çetinkaya, E
Six rhodium-carbene complexes (2a-f) have been prepared and the new compounds characterized by C, H, N analyses, H-1-n.m.r. and C-13-n.m.r. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of rhodium(I)-carbene complex, RhCl(COD)(1,3-dialkylbenzimidazolidin-2-ylidene), (2a-f), to give the corresponding aryl secondary alcohols in good yields.
Selective palladium-catalyzed arylation(s) of benzaldehyde derivatives by N-heterocarbene ligands
(Pergamon-Elsevier Science Ltd, 2005) Gürbüz, N; Özdemir, I; Çetinkaya, B
The 2- or 2,6-position(s) of aromatic aldehydes were directly and selectively arylated with aryl chlorides or bromides in the presence of a catalytic system prepared in situ from Pd(OAC)(2), imidazolinium chlorides (1-5) and Cs2CO3. (c) 2005 Elsevier Ltd. All rights reserved.
Small-dose capsaicin reduces systemic inflammatory responses in septic rats
(Lippincott Williams & Wilkins, 2004) Demirbilek, S; Ersoy, MO; Demirbilek, S; Karaman, A; Gürbüz, N; Bayraktar, N; Bayraktar, M
We investigated the influence of small- and large-dose capsaicin in modulating systemic inflammatory responses during different stages of sepsis in rats. Rats were divided into six groups: group C, control; group S, sepsis; group CLC, small dose of capsaicin (1 mg/kg subcutaneously); group SLC, small dose of capsaicin plus sepsis; group CHC, large dose of capsaicin (150 mg/kg subcutaneously); group SHC, large dose of capsaicin plus sepsis. Rats were made septic by cecal ligation and puncture (CLP). Each group was subdivided into two subgroups. The animals were killed at 9 or 18 h after CLP. Plasma concentrations of calcitonin gene-related peptide (CGRP), tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10, and total nitrite/nitrate (NOx) were measured. Superoxide dismutase and malondialdehyde (MDA) were determined in liver, lung, and heart tissues. CGRP was increased in groups S, CLC, and SLC when compared with the other groups. In the SLC group, plasma concentrations of TNF-alpha, IL-6, NOx, and tissue MDA levels were reduced and IL-10 level was increased when compared with groups S and SHC 18 h after CLP (P < 0.05). Small-dose capsaicin treatment increased antiinflammatory IL-10 levels and attenuated the increases in proinflammatory cytokines, NOx, and tissue MDA in septic rats.
Surface modification of inorganic oxide particles with a carbene complex of palladium
(Springer, 2004) Gürbüz, N; Özdemir, I; Seçkin, T; Çetinkaya, B
The reaction of 1-(2,4,6-trimethylbenzyl)-3-(propyltriethoxysilane) imidazolidinium chloride, with the Pd(OAc)(2) complex proceeded smoothly in DMSO to give the bis[1-(2,4,6-trimethylbenzyl)-3-(propyltriethoxysilane)imidazolidin-2-ylidene] dichloropalladium(II) complex that was grafted onto the surface of amorphous silica. The effects of various factors, such as reaction temperature and time, on the grafting efficiency was evaluated. Inorganic oxide particles that were modified with a carbene complex of palladium(II) were tested for catalytic activity in the Suzuki coupling reaction between phenylboronic acid and several aryl halides.

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