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Öğe Amino alcohol based chiral solvating agents: synthesis and applications in the NMR enantiodiscrimination of carboxylic acids(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Bozkurt, Selahattin; Durmaz, Mustafa; Nazıroğlu, Hayriye Nevin; Yılmaz, Mustafa; Sirit, AbdülkadirFour optically active amino alcohols were synthesized via the ring opening of (R)-N-(2,3-epoxypropyl)phthalimide with (R)-2-phenyl glycinol, (1R,2S)-cis-1-amino-2-indanol, (R)-2-amino-1-butanol and (S)-phenyl ethylamine in 73-93% yields. The enantioselective recognition of these receptors towards the enantiomers of racemic carboxylic acids was studied by (1)H NMR spectroscopy. The molar ratio and the association constants of the chiral compounds with each of the enantiomers of the guests were determined by using Job plots and a non-linear least-squares fitting method, respectively. Large non-equivalent chemical shifts (up to 30.0 Hz) can be achieved in the presence of chiral amino alcohols 2 and 5. Amongst the chiral receptors used, compound 5 was found to be the best chiral shift reagent, and was effective in the determination of the enantiomeric excess of chiral carboxylic acids. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Aminonaftol birimleri taşıyan kiral kaliks[4]aren türevlerinin sentezi ve enantiyomerlerin tanınmasında kullanılması(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2011-09-09) Durmaz, Mustafa; Yılmaz, MustafaBu çalışmada literatürdeki prosedürlere göre dört enantiyosaf (1, 2, 4 ve 6) ve bir rasemik aminonaftol (5) türevi sentezlendi. Rasemik aminonaftol (5), yüksek enantiyomerik fazlalık (ee) ile enantiyomerlerine yarıldı. Aminonaftol türevleri kaliks[4]arenin dibrom türevleri (8?10) ile etkileştirilerek kiral kaliks[4]aren türevleri (11?21) elde edildi. Elde edilen ürünler kristallendirme, kolon kromatografisi ya da her ikisi ile saflaştırılarak yapıları FTIR, 1H NMR, 13C NMR, DEPT ve 2D COSY teknikleriyle aydınlatıldı. Optikçe aktif bileşiklerin çevirme açıları ölçüldü. Bu reseptörlerin çeşitli karboksilik asitlerle enantiyoseçici tanıma özellikleri 1H NMR ve UV/Vis spektroskopisi kullanılarak araştırıldı. Reseptörlerin kiral materyallere karşı farklı tanıma özellikleri gösterdikleri ve konak (host) ile konuk (guest) arasında 2:1 ya da 1:1 komplekslerin oluştuğu belirlendi. Bileşik 12'nin mandelik asitin enantiyosaflığını belirlemede kiral NMR yarma reaktifi olarak kullanılabileceği gösterildi. Ayrıca, kiral kaliks[4]aren türevlerinin varlığında sıvı membrandan bazı amino asit metil esterlerinin (fenil glisin, fenil alanin ve triptofan metil ester) ve mandelik asitin transport çalışmaları yapıldı.Öğe Application of L-Proline Derivatives as Chiral Shift Reagents for Enantiomeric Recognition of Carboxylic Acids(WILEY, 2011) Naziroglu, Hayriye Nevin; Durmaz, Mustafa; Bozkurt, Selahattin; Sirit, AbdulkadirFour proline-derived chiral receptors 5-8 were readily synthesized starting from L-proline. The enantiomeric recognition ability of chiral receptors was examined with a series of carboxylic acids by H-1 NMR spectroscopy. The molar ratio and the association constants of the chiral compounds with each of the enantiomers of guest molecules were determined by using Job plots and a nonlinear least-squares fitting method, respectively. The Job plots indicate that the hosts form 1:1 instantaneous complexes with all guests. The receptors exhibited different chiral recognition abilities toward the enantiomers of racemic guests. Among the chiral receptors used in this study, prolinamide 6 was found to be the best chiral shift reagent and is effective for the determination of the enantiomeric excess of chiral carboxylic acids. Chirality 23:463-471, 2011. (C) 2011 Wiley-Liss, Inc.Öğe Calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids for enantioselective synthesis of alpha-amino acids(PERGAMON-ELSEVIER SCIENCE LTD, 2008) Bozkurt, Selahattin; Durmaz, Mustafa; Yılmaz, Mustafa; Sirit, AbdülkadirThe synthesis of the first calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids has been achieved in two steps from p-tert-butylcalix[4]arene. The catalytic efficiency of the chiral calix[4]arenes 3a-c was evaluated by carrying out the phase-transfer alkylation of N-(diphenylmethylene)glycine ethyl ester with benzyl bromide. Various factors that affect the chemical yield and enantio selectivity were also examined. Benzylation of glycine imine 4 using calix[4]arene- based dimeric catalyst 3a as a chiral phase-transfer catalyst in toluene/CHCl3 mixture (7:3 v/v) at 0 degrees C gave the best enantioselectivities and yields in the presence of aqueous NaOH. (C) 2008 Elsevier Ltd. All rights reserved.Öğe Chiral calix[4]arenes bearing aminonaphthol moieties as membrane carriers for amino acid methyl esters and mandelic acid(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Durmaz, Mustafa; Bozkurt, Selahattin; Nazıroğlu, Hayriye Nevin; Yılmaz, Mustafa; Sirit, AbdülkadirChiral calix[4]arene derivatives functionalized at the lower rim with chiral aminonaphthol units have been prepared. The structures of these receptors were characterized by a combination of (1)H NMR, (13)C NMR, FTIR and elemental analysis. The transport of amino acid derivatives (phenylglycine, phenylalanine and tryptophan methyl ester hydrochlorides) and mandelic acid were studied through a bulk liquid membrane in the presence of chiral calix[4]arene derivatives. The transport rate and enantioselectivity of the amino acid esters studied depended mainly upon the structure of the chiral receptors. The influence of calixarene and amino acid ester structures upon transport through a liquid membrane is discussed. The receptors with hydrogen bonding sites and aromatic groups showed considerable higher transport rates and stereoselectivities. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Chiral calix[4]azacrowns for enantiomeric recognition of amino acid derivatives(PERGAMON-ELSEVIER SCIENCE LTD, 2009) Demirtaş, Havva Nur; Bozkurt, Selahattin; Durmaz, Mustafa; Yılmaz, Mustafa; Sirit, Abdülkadirin this study the synthesis of novel chiral calix[4]azacrown derivatives has been reported. The enantioselectivity of Chiral receptors was investigated by using UV-vis spectroscopy. All the chiral calix[4]arene derivative,; exhibited certain chiral recognition toward the enantiomers of phenylalanine (Phe-OMe.HCl) and alanine methyl ester hydrochlorides (Ala-OME.HCl). As a chiral receptor, the furfuryl-armed calix[4]azacrown ether 7 has the best enantiomeric discriminating ability for alpha-amino acid ester hydrochlorides (up to K-L/K-D 2.08, Delta Delta G(0) 1.82 KJ mol (1)) in CHCl3. The enantiomeric recognition abilities for 1,guests are also discussed from a thermodynamic point of view. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Chiral mono and diamide derivatives of calix[4]arene for enantiomeric recognition of chiral amines(WILEY-BLACKWELL, 2008) Kocabaş, Erdal; Durmaz, Mustafa; Alpaydın, Sabri; Sirit, Abdulkadir; Yılmaz, MustafaNovel chiral mono and diamide derivatives of calix[4]arene have been prepared from the aminolysis reaction of 5,11,17,23-tetra-tert-butyl-25,27-dietboxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 1 and 25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 2 with chiral (S)-(-)-1-phenylethylamine (PEA) and (1S,2S)-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol, respectively. Spectrophotometric titrations have been performed in CHCl3 at 20-30 degrees C in order to obtain the binding constants (K) and the thermodynamic quantities (Delta H and Delta S) for the stoichiometric 1:1 inclusion complexation of various chiral amines with these new host compounds. Preliminary experiments were undertaken to confirm the complexation properties of receptors 9 and 13 with PEA by H-1 NMR in CDCl3 at room temperature. The molecular recognition abilities and enantioselectivities for guests (R and S)-(x-PEA and (R and S)-cyclohexylethylamine (CHEA) are discussed from a thermodynamic point of view.Öğe Chiral Schiff Base Derivatives of Calix[4]arene: Synthesis and Complexation Studies with Chiral and Achiral Amines(Pergamon-Elsevier Science Ltd, 2006) Durmaz, Mustafa; Alpaydın, Sabri; Sırıt, Abdulkadir; Yılmaz, MustafaNovel chiral Schiff base derivatives of calix[4]arenes 1-3 have been prepared from the reaction of 5,17-diformyl-25,27-dipropoxy-26,28-dihydroxycalix[4]arene 4 with (S)-(-)-1-phenylethylamine, (R)-(-)-1-cyclohexylethylamine, and (R)-(-)-2-heptylamine, respectively, by a convenient method in 69-80% yields. Spectrophotometric titrations have been performed in CHCl3 at 20-30 degrees C in order to obtain the binding constants (K) and thermodynamic quantities (Delta H and Delta S) for the stoichiometric 1:1 inclusion complexation of various amines with these new host compounds. The molecular recognition abilities and enantioselectivity for guests (R)- and (S)-alpha-phenylethylamine, 3-morpholinopropylamine and n-butylamine are discussed from a thermodynamic point of view.Öğe Enantiomeric recognition of amino acid derivatives by chiral Schiff bases of calix[4]arene(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Durmaz, Mustafa; Alpaydın, Sabri; Sirit, Abdulkadir; Yılmaz, MustafaNovel calix[4]arene Schiff bases bearing chiral substituents both on the upper and the lower rims have been developed. These chiral receptors exhibit good chiral recognition ability towards alpha-amino acid ester hydrochlorides (up to K-D/K-L = 4.36, Delta Delta G(O) = - 3.65 kJ mol(-1)) in CHCl3. The molecular recognition abilities and enantioselectivities for guests are also discussed from a thermodynamic point of view. (c) 2007 Elsevier Ltd. All rights reserved.Öğe Kaliks[4]arenin homokiral Schiff bazı türevlerinin sentezi ve ekstraksiyon özelliklerinin incelenmesi(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2007-07-10) Durmaz, Mustafa; Sırıt, AbdulkadirBu çalışmada kaliks[4]aren'in kiral üç yeni Schiff bazı türevi (5, 6 ve 7); 25,27-Dipropoksi-26,28-dihidroksi-15,17-dialdehitkaliks[4]aren (4) sırasıyla (S)-(?)- 1-feniletilamin, (R)-(?)-1-siklohekziletilamin ve (R)-(?)-2-heptilamin ile tepkimeye sokularak elde edilmiştir. Kaliks[4]arenin kiral Schiff bazı türevleri kiral ve akiral aminlerin moleküler tanınma çalışmalarında ve amino asitlerin faz transfer ekstraksiyonunda kullanılmıştır. p-tert-bütilkaliks[4]aren ve kaliks[4]arenin kiral tartarik ester türevleri (9 ve 10) literatürdeki metodun geliştirilmesiyle sentezlenmiş ve 10 nolu bileşik para köşelerinden seçimli formilasyon ile aldehit türevi (11) elde edilmiştir. Kiral kaliks[4]aren türevleri bazı amino asitlerin faz transfer ekstraksiyonunda kullanılmıştır. Ayrıca bu bileşiklerin feniletil amin ve 1,2- propandiol guestlerine karşı kiral tanınma özellikleri 1H NMR spektroskopisi kullanılarak incelenmiştir. Gerçekleştirilen tüm reaksiyonlar İTK ile izlenmiş ve elde edilen ürünler kolon kromatografisi ile saflaştırılarak yapıları IR ve 1H NMR, 13C NMR ve FAB MS teknikleriyle aydınlatıldıktan sonra kiral bileşiklerin optik çevirme açıları ölçülmüştür..Öğe Synthesis and chiral recognition properties of two novel chiral calix[4]arene tartaric ester derivatives(PERGAMON-ELSEVIER SCIENCE LTD, 2006) Karaküçük, Ayşegül; Durmaz, Mustafa; Sirit, Abdülkadir; Yılmaz, Mustafa; Demir, Ayhan S.Two new chiral calix[4]arene derivatives containing tartaric acid ester moieties were synthesized. The chiral calix[4]arenes are in a 'cone' conformation according to NMR spectroscopy. The chiral recognition capabilities of 1-4 toward the guests, 1,2-propanediol and serine methyl ester hydrochloride (SerOMe), were investigated (H-1 NMR spectroscopy). The extraction properties of compounds 1 and 2 toward selected alpha-amino acid methyl esters were also studied. (c) 2006 Elsevier Ltd. All rights reserved.Öğe Synthesis and dichromate anion sorption of silica gel-immobilized calix[4]arenes(ELSEVIER SCIENCE BV, 2009) Bozkurt, Selahattin; Kocabaş, Erdal; Durmaz, Mustafa; Yılmaz, Mustafa; Sirit, AbdülkadirThree new silica gel-immobilized calix[4]arene polymers 9-11 have been prepared via modification of calix[4]arene mono amido derivatives 3-5 with 3-aminopropyl triethoxysilane (APTES) and activated silica gel, respectively. The polymers were characterized by Fourier transform infrared spectroscopy, elemental analysis and thermal gravimetric analysis. The solid-liquid extraction properties of ligands 3-5 along with their immobilized derivatives 9-11 towards dichromate (HCr2O7-/Cr2O72-) anions were reported. It was found that these calix[4]arene-based polymers have high extraction abilities towards dichromate anions as compared to their monomeric precursors. (C) 2008 Elsevier B.V. All rights reserved.Öğe Synthesis of 1,3-(distal) diamide substituted calix[4]arene based receptors for extraction of chromium (VI)(TAYLOR & FRANCIS LTD, 2007) Durmaz, Mustafa; Bozkurt, Selahattin; Sirit, Abdülkadir; Yılmaz, MustafaThe synthesis of novel diamide derivatives of calix[4]arene by aminolysis of calix[4]arene diesters was reported. The H-1 and C-13 NMR, data showed that the synthesized compounds exist in the cone conformation. The complexation properties of these calix[4]arenes have been studied towards Cr2O7=/HCr2O7- anions and it has been found that the protonated alkyl ammonium forms of calix[4]arene diamide derivatives (5,11,17,23-tetra-tert-butyl-25,27-(diethylpiperidineacetamido)26,28- dihydroxy-calix[4]arene 3 and 25,27-(diethyl-piperidineacetamido)26,28-dihydroxycalix[4]arene 4) are effective extractants for transferring HCr2O7-/Cr2O7= anions.Öğe Synthesis of calix[4]arene mono and diamide derivatives and selective complexation of alkali and alkaline earth cations(TAYLOR & FRANCIS INC, 2007) Bozkurt, Selahattin; Durmaz, Mustafa; Sirit, Abdülkadir; Yılmaz, MustafaThe synthesis of mono and diamide derivatives of the p-tert-butylcalix[4]arenes/calix[4]arenes from the reaction of 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 1 and 25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4] arene 2 with various primary amines were reported. The effect of reaction time and steric hindrance of the primary amines used on the reactions have been investigated. All the amide derivatives of calix[ 4] arene are in a cone conformation according to the H-1-NMR doublet-doublet pattern of the protons of the methylene groups between the aromatic rings. The complexing properties of these compounds toward selected alkali and alkaline earth metal cations are also studied. It has been observed that receptor 8 is a selective extractant for Cs+ and Sr2+ cations.Öğe Synthesis of chiral calix[4]arenes bearing aminonaphthol moieties and their use in the enantiomeric recognition of carboxylic acids(ROYAL SOC CHEMISTRY, 2011) Durmaz, Mustafa; Yılmaz, Mustafa; Sirit, AbdülkadirTwo armed chiral calix[4]arenes 8-16 functionalized at the lower rim with chiral aminonaphthol units have been prepared and the structures of these receptors characterized by FTIR, H-1, and C-13, DEPT and COSY NMR spectroscopy and elemental analysis. The enantioselective recognition of these receptors with various carboxylic acids has been studied by H-1 NMR and UV/Vis spectroscopy. The receptors exhibited different chiral recognition abilities towards the enantiomers of racemic materials and formed 2 : 1 or 1 : 1 complexes between host and guest. It was also demonstrated that chiral calix[4]arenes 9 and 16 could be used as chiral NMR solvating agents to determine the enantiomeric purity of mandelic acid.Öğe Synthesis of new chiral calix[4]azacrowns for enantiomeric recognition of carboxylic acids(PERGAMON-ELSEVIER SCIENCE LTD, 2008) Demirtaş, Havva Nur; Bozkurt, Selahattin; Durmaz, Mustafa; Yılmaz, Mustafa; Sirit, AbdülkadirTwo novel chiral calix[4]azacrown ethers 4 and 5 bearing a furfuryl group on the nitrogen atom were developed by the reaction of dibromo- or ditosyl derivatives of p-tert-butylcalix[4]arenes 2 and 3 with a chiral diol, 1. The enantioselective recognition of these receptors towards the enantiomers of racemic carboxylic acids has been studied by H-1 NMR spectroscopy. The molar ratio and the association constants of the chiral compounds 4 and 5 with each of the enantiomers of guest molecules were determined by using job plots and a nonlinear least-squares fitting method, respectively. The job plots indicate that both of the hosts form 1:1 instantaneous complexes with (R)- OF (S)-mandelic acid and (L)- or (D)-dibenzoyl-tartaric acid. The receptors exhibited different chiral recognition abilities towards the enantiomers of racemic guests. (C) 2008 Elsevier Ltd. All rights reserved.
