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    Asymmetric reduction of acetophenone using lithium aluminium hydride modified with some novel amino alcohol Schiff bases
    (Pergamon-Elsevier Science Ltd, 2005) Tümerdem, R; Topal, G; Turgut, Y
    Some new chiral Schiff bases have been prepared in good yields from various carbonyl groups and two 2-amino alcohols. LiAlH4 was treated with different equivalents of the Schiff bases. Enantioselective reduction of acetophenone is achieved in high chemical yield (up to 93%) with moderate enantiomeric excess (up to 22%) by use of the new reducing agents. (C) 2005 Elsevier Ltd. All rights reserved.
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    The enantiomeric recognition of chiral organic ammonium salts by chiral monoaza-15-crown-5 ether derivatives
    (Pergamon-Elsevier Science Ltd, 2004) Turgut, Y; Sahin, E; Togrul, M; Hosgören, H
    Novel chiral monoaza-15-crown-5 ether derivatives 1 and 2 were prepared frorn L-phenylalaninol and L-leucinol, respectively. The effect of the substituent at the stereogenic center on chiral recognition and enantioselectivity were investigated. Binding constant (K), free-energy changes (-DeltaG(0)), enthalpy change (DeltaH), and entropy change (DeltaS) values were determined with enantiomers of organic ammonium salts by a titration UV-vis method in CHCl3. (C) 2004 Elsevier Ltd. All rights reserved.
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    A practical synthesis of chiral 3-aryloxy-1,2-propanediols
    (Science Reviews 2000 Ltd, 2005) Karakaplan, M; Turgut, Y; Hosgören, H
    Chiral 3-aryloxy-1,2-propanediols (1-5) of > 96% ee were obtained in high yield by the nucleophilic addition of substituted phenols to chiral glycidol in the presence of piperidine hydrochloride as catalyst.
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    The solvent extraction of boron with synthesized aliphatic 1,3-diols
    (Taylor & Francis Inc, 2004) Karakaplan, M; Tural, S; Tural, B; Turgut, Y; Hosgören, H
    A variety of aliphatic 1,3-diols (4a-c, 5a-c, 6a-c) was synthesized from beta-hydroxy carbonyl compounds (1-3) for potential use in the solvent extraction of boron. Primary-secondary and primary-tertiary alcohol structures of 1,3-diols substituted with isopropyl, isobutyl, and isopentyl groups have been demonstrated to be very efficient for the solvent extraction of boric acid from aqueous solutions. The extraction ability of 2,2,5-trimethyl-1,3-hexanediol (5b) was investigated as a function of 5b concentration, solution pH, solvent properties, and stripping conditions. Extraction efficiency increased with increasing concentration of 5b, and the best extraction of boron (96.8%) was found to be at an equilibrium pH of 2 with 0.5 M of 5b. Chloroform, toluene, chlorobenzene, 2-octanol, and n-amyl alcohol were found to be suitable solvents for the solvent extraction of boron. The boron complex can be recovered from the organic phase by treatment with an aqueous solution of sodium hydroxide. The highest ratio (96.7%) of boron was recovered by 0.1 M of sodium hydroxide solution.
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    Synthesis of chiral monoaza-15-crown-5 ethers from L-valinol and the enantiomeric recognition of chiral amines and their perchlorates salts
    (Pergamon-Elsevier Science Ltd, 2003) Turgut, Y; Hosgören, H
    A practical synthesis of chiral monoaza-15-crown-5 ethers I and 2 has been achieved from L-valinol. The molecular recognition by these chiral crown ethers for (RS)-alpha-phenylethylamine, (RS)-alpha-(1-naphthyl)ethylamine and their perchlorate salts has been characterized by UV-vis. (C) 2003 Elsevier Ltd. All rights reserved.
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    Synthesis of new chiral diaza 18-crown-6 ethers from chiral amines
    (Science Reviews 2000 Ltd, 2003) Demirel, N; Turgut, Y; Hosgören, H
    Practical syntheses of versatile building blocks of crown ethers 1 and 2, chiral amine precursors 3-6 and chiral diaza 18-crown-6 ethers 7-12 are reported starting from chiral amines.
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    Synthesis of novel chiral C2-symmetric diaza-18-crown-6 ether derivatives and their enantioselective recognition of amino acid derivatives
    (Springer, 2006) Turgut, Y; Demirel, N; Hosgören, H
    New chiral diaza-18-crown-6 ether derivatives, 5 and 6 were synthesized from (R)-(-)-2-amino-1-butanol. These chiral artificial receptors exhibit pronounced chiral recognition toward the enantiomers of L- and D- amino acid derivatives. The highest enantioselectivity was observed in the case of Trp-OMe center dot HCl (K-D/ K-L= 12.5).
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    Synthesis of novel chiral monoaza-15-crown-5 ethers and their molecular recognition of amino acid esters
    (Science Reviews 2000 Ltd, 2004) Turgut, Y; Isgin, ES; Hosgören, H
    The chiral monoaza-15-crown-5 ethers 4 and 5 were prepared from L-phenylalaninol and L-leucinol, respectively. The molecular recognition of these chiral crown ethers for L-amino acid ethyl esters was characterised by UV-visible spectroscopy. Binding constants (K-a), free-energy changes (-DeltaGdegrees), enthalpy changes (DeltaH) and entropy change (DeltaS) values were determined for hosts 4 and 5 with L-amino acid ethyl ester hydrochlorides in CHCl3.
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    Synthesis of R-(-)-2-ethyl-N-benzyl (monoaza-15-crown-5) and the crystal structure of its sodium perchlorate complex
    (Springer, 2001) Özbey, S; Hosgören, H; Turgut, Y; Topal, G
    A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P2(1) with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Angstrom, beta = 105.51(1)degrees, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are two molecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na-O-eth (etheric) distances are 2.364(6), 2.317(7) Angstrom and the Na-N distances are 2.679(6), 2.611(7) Angstrom; the Na-O(ClO4) contacts are 2.497(7) and 2.257(10) Angstrom, for A and B, respectively.