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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 Chemical constituents and biological activities of cirsium leucopsis, c. sipyleum, and c. eriophorum(Walter de Gruyter, 2015-03-19) Boğa, Mehmet; Köseoğlu Yılmaz, Pelin; Barış Cebe, Deniz; Fatima, Mashhad; Siddiqui, Bina S.; Kolak, UfukTwo endemicCirsiumspecies,C. leucopsisDC. andC. sipyleumO. Schwarz, andC. eriophorum(L.) Scop. growing in Turkey were investigated to establish their secondary metabolites, fatty acidcompositions, and antioxidant and anticholinesterase potentials. Spectroscopic methods were usedto elucidate the structures of thirteen known compounds (p-hydroxy-benzoic acid, vanillic acid,cis-epoxyconiferyl alcohol, syringin, balanophonin, 1′-O-methyl-balanophonin, apigenin, kaempferol-3-O-β-D-glucopyranoside, kaempferol-3-O-α-L-rhamnopyranoside, taraxasterol, taraxasterol acetate,β-sitosterol,β-sitosterol-3-O-β-D-glucopyranoside).cis-Epoxyconiferyl alcohol and 1′-O-methyl-balanophonin were isolated for the first time fromCirsiumspecies. Palmitic acid (47.1 %) was foundto be the main fatty acid ofC. leucopsis, linoleic acid in bothC. sipyleum(42.1 %) andC. eriophorum(37.8 %). Assays ofβ-carotene bleaching, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) freeradicals, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium (ABTS) cation radicals,and superoxide anion radicals, as well as cupric reducing antioxidant capacity (CUPRAC) were usedto determine the antioxidant activities of the extracts and isolated compounds. Vanillic acid, balano-phonin, and kaempferol-3-O-α-L-rhamnopyranoside exhibited strong antioxidant activity. Taraxa-sterol was a potent inhibitor of acetyl- and butyrylcholinesterase activity, respectively.
