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Öğe Design of l -lysine-based organogelators and their applications in drug release processes(American Chemical Society, 2019) Kaplan, Şeref; Çolak, Mehmet; Hoşgören, Halil; Pirinççioğlu, NecmettinThis work reports on the synthesis of three new l-lysine-based organogelators bis(N2-alkanoyl-N6-l-lysyl ethylester)oxalylamides, where alkanoyls are lauroyl, myristoyl, and palmitoyl. The gels of these gelators were prepared with high yields in eco-friendly solvents commonly used in cosmetics such as ethyl and isopropyl esters of lauric and myristic acids, liquid paraffin, 1-decanol, and 1,2-propanediol. Fourier transform infrared measurements revealed the involvement of intermolecular hydrogen bonds in the gelation. Scanning electron microscopy images of xerogels indicated different morphologic patterns with regard to the alkanoyl chain length and the solvent employed in their preparation. The gel formation was supported by rheological measurements. Three gels prepared in liquid paraffin were loaded with naproxen (Npx) with a quite high loading capacity (up to 166.6% as percentage of gelator) without gel disruption. The release of Npx from the gel matrix into the buffered solution at physiologic pH was evaluated using UV-vis spectroscopy. The results revealed that the release rate of Npx from the organogels significantly retarded with increasing organogelator concentration, whereas it enhanced with increasing Npx concentration. The rate was also found to be pH-dependent; the lower the pH, the lower the rate. Furthermore, molecular dynamic calculations performed on the octamer of myristoyl-bearing gelator (N2M/N6Lys) in 1,2-propanediol provided useful information regarding the structural properties of the gels, which may be of interest to interpret the structure of the gel matrix. Altogether, this work provided valuable outcomes, which may be relevant to the pharmaceutical industry. It may be suggested that l-lysine-based gels have potentials in the delivery of nonsteroidal anti-inflammatory drug molecules. Besides, the release of the drug can be fine-tuned by the correct choice of gelator-solvent combination.Öğe Enantioselective recognition of ammonium perchlorate salts by optically active monoaza-15-crown-5 ethers(Wiley, 2004) Toğrul, Mahmut; Turgut, Yılmaz; Hoşgören, HalilChiral monoaza-15-crown-5 ethers (1, 2) were prepared from (R)-(-)-2-amino-1-butanol in high yield. The chiral monoaza-15-crown-5 ethers were purified directly as NaClO4 complexes. Molecular recognition by these chiral monoaza-crown ethers of (R)- and (S)-PhEtHClO4 and (R)- and (S)-NapEtHClO(4) as characterized by UV-vis spectroscopy. The order of enantiomeric selectivity is (R)- > (S)- PhEtHClO4 and (S)- > (R)-NapEtHClO(4) for 1. In the case of 2 it was (R)- > ($)-PhEtHClO4 and (R)- > (S)-NapEtHClO(4). The cavity of macrocycle and steric hindrance of the benzene units appears to play an important role in recognition. (C) 2004 Wiley-Liss, Inc.Öğe Enantioselective transport and liquid-liquid extraction of amino acids as their potassium and sodium salts by optically active diaza-18-crown-6 ethers(Wiley, 2004) Demirel, Nadir; Bulut, Yasemin; Hoşgören, Halil; 0000-0002-8571-5552Complexation of amino acids as their sodium and potassium salts by optically active diaza crown ethers has been investigated in transport across bulk liquid membranes containing the carriers and in extraction experiments. The observed enantio selectivity was achieved by (noncovalent) steric and repulsive interactions between the side arm of the crown ether and functional group(s) of the amino acids. The highest enantio selectivity was observed in the case of tryptophan. (C) 2004 Wiley-Liss, Inc.Öğe Facile synthesis of mono and dibenzo N, N-disubstituted diaza 18-crown-6 derivatives(Hetero Corporation, 2001) Topal, Giray; Demirel, Nadir; Toğrul, Mahmut; Turgut, Yılmaz; Hoşgören, Halil; 0000-0002-7056-3912; 0000-0002-8571-5552; 0009-0000-3823-0467This study represents a facile synthesis of building blocks (1-3) of crown ethers and amine precoursers (4a-d). The study also involves synthesis of mono and dibenzo N,N'-disubstituted diaza 18-crown-6 derivatives with high yield without chromatographic purification and high vacuum distillation. The complex ability of host the ethers was evaluated in terms of structural modification.Öğe Investigation of some 1-3-diols for the requirements of solvent extraction of boron: 2,2,6-trimethyl-1,3 heptanediol as a potential boron extractant(2007) Hoşgören, Halil; Tural, Servet; Tural, BilsenEighteen 1,3-diols were synthesized and their structure and distribution ratio for the solvent extraction of boron were studied. Diols with a high distribution ratio $(D_{B(OH)_3} > 10)$ were investigated for the requirements of solvent extraction of boron. Their extraction capacity, and solubility in aqueous phase and in organic diluents were investigated by comparison to -ethyl-1,3-hexanediol (EHD), which is widely used as a boron extractant. Among a series of 1,3 diols, 1-benzyl-2,2-dimethyl-1,3-propanediol (4a) and 2,2,6-trimethyl-1,3-heptanediol (3a) were found to have very low solubility in the aqueous phase compared to the others. IPD (3a) was found to have a high solubility in aliphatic diluents such as kerosene. IPD,which has good solubility properties for the solvent extraction of boron, was studied in detail, including dependence of pH, diol concentration, and stripping facility, and in various organic diluents.Öğe Kiral monoza ve diaza taç eter sentezi ve enantiyoselektif Michael katılmasında katalizör olarak kullanılması(2001) Turgut, Yılmaz; Demirel, Nadir; Topal, Giray; Toğrul, Mahmut; Özbey, Süheyla; Hoşgören, Halil[Abstract Not Available]Öğe Lysine-based two-component organogelator: Naproxen carrier soft material(John Wiley and Sons Inc, 2023) Çolak, Mehmet; Kaya, Gülşen; Hayaloğlu, Ali Adnan; Demirel, Nadir; Hoşgören, HalilWe demonstrated that Nϵ -alkanoyl-L-lysine ethyl ester/N-alkanoyl-L-phenylalaninate gelling agents were constructed as a two-component gelling strategy and applied as drug carriers in friendly solvents commonly used. Our designs are expected to have an edge in contrast to the other lipid-based systems due to cheap raw materials, reducing the required amount of carrier, low molecular weight, ease of loading, simple dose adjustability, skin spreadability, and improved drug retention times. It could be loaded with Naproxen (Npx) with a high loading efficiency (up to 100 % as a percentage of gelator) without gel disruption. A complementary in vitro drug release study under specific pH was conducted and performed at different drug and gelator concentrations. These results reveal that the release of Npx from the supramolecular organogels was significantly retarded with increasing organogelator engagement from 0.46 % to 0.92 %, the initial release rate considerably reduced, from 18.75 % to 7.21 %, respectively; that is release rate shows a 2.6-fold decrease; this result showed that the gelator concentration could control drug release. whereas the increasing Npx concentration enhanced it. Altogether, this work produces valuable outcomes, which may be relevant to the pharmaceutical industry, suggesting that new platforms may deliver NSAID (non-steroidal anti-inflammotory drug) molecules.Öğe Preparation of some N-alkyl nitro anthranilic acid derivatives and use in solvent extraction(1995) Topal, Giray; Hoşgören, Halil[Abstract Not Available]Öğe Resolution of (±)-?-Methylphenylethylamine by a Novel Chiral Stationary Phase for Pirkle-Type Column Chromatography(Wiley, 2010) Yılmaz, Hayrullah; Topal, Giray; Çakmak, Reşit; Hoşgören, Halil; 0000-0002-5275-6606; 0000-0003-0401-7419; 0000-0002-7056-3912In this study, a new Pirkle-type chiral column stationary phase for resolution of beta-methylphenylethyl amine was described by using activated Sepharose 4B as a matrix, L-tyrosine as a spacer arm, and an aromatic amine derivative of L-glutamic acid as a ligand. The binding capacities of the stationary phase were determined at different pH values (pH = 6, 7, and 8) using buffer solutions as mobile phase, and enantiomeric excess (ee) was determined by HPLC equipped with chiral column. The ee was found to be 47%. Chirality 22:252-257, 2010. (C) 2009 Wiley-Liss, Inc.Öğe Solvent extraction of $La^{3+}$ with ethylenediamine-N,N'-ditetradecyl-N,N'-diacetic acid (EDDAT) in dichloromethane(1998) Hoşgören, Halil; Yurdakoç, MürüvvetEthylenediamine-N,N'-ditetradecyl-N,N'-diacetic acid (EDDAT) was synthesized for the solvent extraction of $La^{3+}$ . EDDAT was prepared from ethylenediamine-N,N'-diacetic acid (EDDA) and tetrade-cyl bromide in a basic n-amylalcohol-ethanol-water solvent system. The structure of this new extracting reagent was identified according to spectroscopic data, i.e. $^{13}C$ NMR, $^1H$ NMR, and elemental analysis results. The solvent extraction of $La^{3+}$ with EDDAT in dichloromethane was studied as a function of parameters of the aqueous and organic phases. The optimal extraction conditions were determined. The extraction yield increased with a decrease in hydrogen ions in the aqueous phase. Stripping of the $La^{3+}$ loaded organic phase was achieved with HCl aqueous solution. The effect of stripping as a function of the HC1 concentration was also studied.Öğe Some aromatic derivatives of 1,4,7,10,13,16-hexaoxacyclooctadecane(Springer Verlag, 1981) Hoşgören, Halil; Erk, Çakıl[Abstract Not Available]Öğe Synthesis of a new stable peristatic chiral pseudocryptand for simultaneous binding of boron and sodium(Hetero Corporation, 2005) Toğrul, Mahmut; Topal, Giray; Yurdakoç, Mürüvvet; Hoşgören, HalilA new selective molecular receptor, borocryptate, based on the combination of the 15 membered ring diazatrioxa core and two saligenin units as binding sites for boron has been described. The resulting peristatic chiral compound is stable in air and easily converted to polynuclear complex, Na-borocryptate, without using an inert atmosphere.Öğe Yeni yan kollu krown eterlerin sentezi ve mono ve divalent katyonların sıvı-sıvı ekstraksiyonda kullanımları(1994) Hoşgören, Halil; Toğrul, Mahmut; Temel, Hamdi; Karakaplan, MehmetLiteratürde verilen sentez yöntemlerinde 4,13-diaza-18-crown-6'nın N,N'-disübstitüe türevlerinin kısa alkil gruplu olanları hariç, pahalı bir çıkış maddesi olan 4,13-diaza-18-crown-6'nın alkillenmesiyle sentezlendiler. Bu çalışmada 4,13-diaza-18-crown-6'nın hazırlanan bütün N,N'-disübstitüe türevleri trietilenglikol ditosilat ile uygun bir N,N'-disübstitüe-4,7-dioksa-l,10-diazadekamn etkileştirilmesiyle hazırlanmıştır. Bu amaçla beş yeni N,N'-disübstitüe-a,oû-diamino-alifatik eter türevi sentezlenerek pikrat ve dipikrat türevleriyle karakterize edildiler. Ayrıca N,N-disübstitüe-4,13-diaza-18-crown-6' nın Na+,K+, Ca2+, Ba2+ ,Sr2+ ,Pb2+ ve Ag+ perklorat tuzlanyla kompleksleri hazırlandı. Bu yeni komplekslerin element analizi, ve IR, $^1H$ NMR, $^{13}C$ NMR gibi spektroskopik teknikleriyle yapılan doğrulandı.
