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Öğe New drug loading systems: Using two component gelling strategy(Ankara Üniversitesi, 2015) Çolak, Mehmet; Evcil, Murat; Barış Cebe, Deniz; Hoşgören, HalilÖğe Asymmetric organocatalytic efficiency of synthesized chiral β-amino alcohols in ring-opening of glycidol with phenols(Springer Nature, 2012-04-11) Aral, Tarık; Karakaplan, Mehmet; Hoşgören, HalilA series of novel chiral β-amino alcohols 3-5 and 7-10 were synthesized by regioselective ring opening of epoxides and chiral amines with a straightforward method in high yields (up to 99 %). Kinetic resolution of racemic glycidol with phenols was achieved by using chiral amino alcohols as organocatalysts. Amino alcohols 5, 8 and 10 exhibited the highest enantioselectivities with p-cresol, phenol, and p-methoxyphenol by 63, 65, 58 % ee, respectively. The moderate enantioselectivities were observed with catalyst 9b towards all the nucleophiles (34-48 % ee). The ee values of the desired 3-aryloxy-1, 2-diols were determined by HPLC. This study presents an attractive tool for the synthesis of β-blockers and structurally complex molecules.Öğe Organogels as novel carriers for dermal and topical drug delivery vehicles(Kimyagerler Derneği, 2017) Barış Cebe, Deniz; Çolak, Mehmet; Hoşgören, HalilÖğe Organogels as novel carriers for dermal and topical drug delivery vehicles(Elsevier, 2016-11-24) Uzan, Serhat; Barış Cebe, Deniz; Çolak, Mehmet; Aydın, Haluk; Hoşgören, HalilAminoalcohol based bis-(aminoalcohol)oxalamides (BAOAs) (1,6-amino alcohol=leucinol, isoleucinol, valinol, phenylglycinol, phenylalaninol and 2-amino-1-butanol) have been explored to develop drug depot systems and illustrated as a novel dermal and topical drug delivery vehicle for non-steroidal anti-inflammatory drug molecules. FAE's (Fatty acid ethyl and isopropyl esters) with different chain lengths, ethyl laurate, ethyl myristate, ethyl palmitate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, have been chosen as they are biocompatible organic fluids used typically in cosmetic industry. Ibuprofen (Ib), acting as a model drug, was entrapped in the supramolecular organogels. The release behavior of Ib molecules in the supramolecular organogels was investigated by using UV–vis spectroscopy. The influence of the organogelator and drug concentration, pH values of the accepting media, and nature of solvent (different FAE's) on the release behavior of Ib was investigated under static conditions. The results indicated that the release rate of Ib from the supramolecular organogels was effectively retarded with an increase of the organogelator concentration. Also, the release rates of Ib increased on increasing the Ib content. Furthermore, the release behavior of Ib was found to be different at various pH values in buffers as accepting media. The study of the release kinetics indicated that the release behavior of Ib was in accord with the Higuchi equation and the diffusion-controlled mechanism involved in the Fickian model. These observations indicate that bis-(aminoalcohol)oxalamides gels may act as delivery vehicles for non-steroidal anti-inflammatory drug molecules and also show that the release profiles for such systems can be fine-tuned by the correct choice of gelator-FAE combination.Öğe Novel bis(aminoalcohol)oxalamide organogelators and their diglycolylamide analogs: evaluation of gelation efficiency in various organic fluids(TÜBİTAK, 2017-11-10) Çolak, Mehmet; Pirinççioğlu, Necmettin; Hoşgören, Halil; Barış Cebe, DenizThree modular types of bis(aminoalcohol)oxalamides (1, 4, and 7) and bis(aminoalcohol)diglycolylamide (8) gelators have been prepared by the reaction of the respective aminoalcohols with oxalyl and digycolyl methylesters as potential low-molecular-weight organogelators. The gelation properties of these amides have been evaluated in various aromatic organic solvents (xylene, toluene, isopropyl benzene, and aromatic ether type organic fluids such as anisole or α-phenylethylmethylether) as well as the long-chain aliphatic alcohols (1-hexanol, 1-octanol, 2-octanol, and aromatic 1- phenylethanol). The compounds with sec-butyl and ethyl side chains produce good gelation properties in both aromatic and other organic fluids. Furthermore, the common oxalamide linker present in the gelators was replaced by an extended diglycolylamide linker (8) and its behaviors were compared with the benzylic oxalamide analog (3). The gelator (8) gives the best results with aromatic fluid and lauric acid ethyl ester. 1 H NMR studies reveal the existence of temperaturedependent network assembly/dissolution equilibrium and produce Kgel . FTIR was employed to see the effect of hydrogen bonding in the formation of gel network. Thermodynamic parameters regarding gel-to-sol transition were collected with van’t Hoff relationships.Öğe Novel C2-symmetric macrocycles bearing diamide-diester groups: Synthesis and enantiomeric recognition for primary alkyl ammonium salts(American Chemical Society, 2008-03-12) Sünkür, Murat; Barış Cebe, Deniz; Hoşgören, Halil; Toğrul, MahmutWe synthesized a series of novel macrocycles with diamide−diester groups (S,S)-1, (S,S)-2, (S,S)-3, and (R,R)-1, derived from dimethyloxalate and amino alcohols by high dilution technique, and evaluated enantiomeric recognition properties of these macrocycles toward primary alkyl ammonium salts by 1H NMR titration. Taking into account the host employed, important differences were observed in the Ka values of (R)-Am and (S)-Am for (S,S)-1 and (R,R)-1 hosts, KS/KR = 5.55 and KR/KS = 3.65, ΔΔGo = 0.43 and −0.32 kJ mol-1, respectively. There seems a general tendency for the host to include the guests with the same absolute configuration.Öğe Enantioselevtive compexation of chiral lariat crown ethers and chiral primary alkylamonum perchlorates(Turkish Journal Chemistry, 2011-02-01) Aral, Tarık; Köylü, Mehmet Zafer; Kocakaya, Şafak Özhan; Karakaplan, Mehmet; Hoşgören, HalilIn order to investigate the enantiomeric recognition abilities toward 2 chiral alkylammonium perchlorates (AmI, AmII) by 1 H-NMR titration method in CDCl 3, 4 chiral lariat ethers 8-11 with a (p-methoxyphenoxy) methyl flexible side arm were used. The most effective enantiomeric recognition was obtained by LCEs 9 and 11 toward AmII, by KR /KS 6.58 and KS /KR 6.63, respectively. The effect of macroring size, subunit of macroring, and side arm appeared to have strong influence on the binding ability of these alkylammonium ions.Öğe New drug delivery systems: Using two-component gelling system as a highly tunable soft materia(Bahçeşehir Üniversitesi, 2016) Çolak, Mehmet; Evcil, Murat; Barış Cebe, Deniz; Hoşgören, HalilÖğe Two-component organogelators: combination of Nε-alkanoyl-L-lysine with various N-alkanoyl-L-amino acids: additional level of hierarchical control(Taylor & Francis, 2018-10-02) Çolak, Mehmet; Barış Cebe, Deniz; Evcil, Murat; Demirel, Nadir; Hoşgören, HalilSynthesis of two-component organogelation system was performed very easy and concise manner from Nε-palmitoyl-L-lysine ethyl ester and Nε-miristoyl-L-lysine ethyl ester in which they were used as base component and N-lauroyl-L-amino acids (amino acids:, alanine, leucine and phenylalanine as acid components.). And their organogelation properties were examined in different pharmaceutical fluids such as liquid paraffin, fatty acid ethyl, and isopropyl esters. In this way, gelation efficiency was ascertained variations of alkanoyl moieties and combination of different amino acids in the gelator structures. Characterization of gelators was performed via thermal measurement such as Tg and gel–sol enthalpy change; SEM and FTIR as optical methods.Öğe Homochiral bis aminoalcohol oxalamide organogels in fatty acid esters as transdermal penetration enhancers as matrix for transdermal transport of drugs(Ankara Üniversitesi, 2012) Çolak, Mehmet; Kaplan, Şeref; Kaya, Gülşen; Barış Cebe, Deniz; Aydın, Haluk; Hoşgören, Halil
