Browsing by Author "Durucasu, I"

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    Asymmetric synthesis of (S)-dihydrokavain from l-malic acid
    Eskici, M; Karanfil, A; Özer, MS; Kabak, Y; Durucasu, I
    A practical and efficient asymmetric synthesis of (S)-dihydrokavain from known ethyl (S)-2-hydroxy-4-phenylbutanoate which is, in turn, readily available from l-malic acid as a cheap chiral pool material is described using regioselective ring-opening of the 1,2-cyclic sulfate with lithium-3,3,3-triethoxypropiolate and subsequent HgO/H2SO4-mediated lactonization as the key steps. Its opposite enantiomer (R)-dihydrokavain was also synthesized from d-malic acid using the same sequences of reactions for the purpose of optical purity determination. [GRAPHICS] .
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    Optical and photovoltaic properties of salicylaldimine-based azo ligands
    Dinçalp, H; Yavuz, S; Hakli, Ö; Zafer, C; Özsoy, C; Durucasu, I; Içli, S
    A series of azo dyes containing salicylaldimine-based ligands as side chains were prepared and characterized. Absorption and emission data in five solvents of different polarities were studied. Photoirradiation studies under an oxygen atmosphere in water showed that the Schiff base side chains enhanced the photo-oxidative stability of the azo chromophore. The electrochemical properties of the dyes were investigated by a cyclic voltammetry. The synthesized salicylaldimine-based azo dyes gave two irreversible oxidation potentials. Complexation behavior of synthesized compounds with titanium (IV) ions was illustrated by the change in their absorption spectra. These ligands are appropriate sensitizers for anchoring to the TiO2 surface chemically in dye-sensitized solar cell (DSSC) productions. Electron injection capacities to TiO2 and photovoltaic performance of the synthesized salicylaidimine-based azo dyes were tested with DSSC. (C) 2009 Elsevier B.V. All rights reserved.
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    A New Analytical Method for the Determination of Phenolic Compounds and Their Antioxidant Activities in Different Wheat Grass Varieties
    Kardas, TA; Durucasu, I
    In this work, the phenolic content and antioxidant capacity of wheat grass, Turkish Amber Durum wheat was studied. For this purpose Turkish Amber Durum wheat was germinated at three different times (15, 30 and 40 days). All the wheat samples sprouted in the same organic conditions and then dried with air and without sunlight and placed into an incubator at 50 degrees C overnight. The dried and milled amber wheat grass was extracted with ethyl acetate and compared for their antioxidant capacities against the 2,2-diphenyl-1-picrylhydrazyl (DPPH.) radical, and at the same time the total phenolic content (TPC) was determined. Phenolic compounds in the extracts were examined by high performance liquid chromatography (HPLC). In this study, by using a new method, nine standards were separately detected within 50 min by using the HPLC system, as previously reported by other authors. The major phenolics, identified in the wheat grass that consisted of ferulic acid, gallic acid, caffeic acid, p-coumaric acid, ellagic acid, benzoic acid, p-hydroxybenzoic acid, syringic acid, quercetin and bha (butylated hydroxyanisole). The highest antioxidant and antiradical activities were detected in Turkish Amber wheat that sprouted in 15 days. This study demonstrates that the importance of wheat grass is due to its high antioxidant activity Consumption of wheat grass has positive effects on human health such as reduced risk of coronary heart diseases, certain type of cancers and stroke. Due to the high antioxidant effect of wheat grass the aim is to use it as a food preservative. When wheat grass will be used as a natural food preservative, carcinogenic effects of synthetic food preservatives for body would be preserved.
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    APOLAR CONSTITUENTS OF SOME BIOLOGICALLY ACTIVE Dianthus SPECIES FROM WESTERN ANATOLIA
    Durucasu, I; Mutlu, K; Sik, L; Yasa, I; Arda, N; Kirmizigul, S
    The apolar constituents of four Dianthus (Caryophyllaceae) species were determined by GC-MS. Palmitic, linoleic, and oleic acids were detected as dominant components in all species. D. elegans d'Urv. var. elegans had the highest antioxidant activity. All four species also showed considerable antimicrobial activity against S. epidermidis and C. albicans.
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    Fatty acid and, conjugated linoleic acid profiles of infant formulas through direct transesterification of acyl lipids
    Tokusoglu, Ö; Durucasu, I; Akalin, AS; Serin, E; Aksit, S
    Fatty acid (FA) values, including C8:0, C10:0, C12:0, C13:0, C14:0, C16:0, C18:0, C18:1t, C18:1c, C18:2, C18:2 CLA, C20:0, C18:3 and C22:0, in sixteen infant formulas were determined through direct transesterification of acyl lipids with sodium methoxide by capillary gas chromatography. Total FA values ranged from 250.25-256.06 mg/g sample and the conjugated linoleic acid (CLA) (cis-9, trans-11 octadecadienoic acid) values were 1.41-2.02 mg/g sample (p < 0.01) in the infant formulas. The total saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid values were also obtained. The C18:3 (linolenic acid (n-3)) values were 0.63-0.88 mg/g sample, whereas the C18:2 (linoleic acid (n-6)) values ranged from 35.64-35.82 mg/g sample. FA standard mix including CLA had linear calibration curves through the origin (R-2 = 0.9999). The precision of the analytical method was (using C13:0, methyl tri-decanoate, as internal standard) within the 95% confidence limits and the mean recoveries determined for individual fatty acids in infant formulas varied from 99.8 to 100%.