Assoc. Prof. Theses
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Item Organik kimyada dipolar ve sterik etkileşimler(Thesis (Assoc. Prof.) - Bogazici University. Institute of Sciences and Engineering, 1978., 1978.) Özbal, Hadi.Item Katı fazda peptid sentezi(Thesis (Assoc. Prof.) - Bogazici University. Institute of Science and Engineering, 1978., 1978.) Yakalı, Emel.In this work, the syntheses of three new peptides (XXIV-Xxvr, Table 2.2) , each containing 39 amino acids, are reported. N-t-butyloxy-carbonyl-p-choloro-L-phenylalanine (XXVIIa) and N-t-htyloxycarbmyl-L-2- aminoheptanoic acid (XXVIIIa), necessary for the above syntheses, have also been prepared for the first the. These peptides are analogs of the "nonheme" peptide of cytochrame c which is a protein found in all cells having a nucleus.Cytochrame c from different species are known to show differences in their amino acid sequences. Horse heart cytochrame c (XXI) consists of one "heme c" group and 104 amino acid residues in a single polypeptide chain. The 66-104 fragment of this chain, ccmtaining 39 amino acids, is known as the nonheme peptide (XXIII) . The peptides synthesized differ from this nonheme peptide (XXIII) only in one position. In the first peptide (XXIV,) tyrosine-67 has been replaced by p-chloro-l-phenylalanine; in the second one, (XXIV) tyrosine-67 by p-chloro-L-phenylalanine; and in the third one (XXVI)', lyshe-79 by L-2-amhoheptanoic acid. Combination of these analogs with the native 1-65 heme peptide (XXIIb) of horse heart cytochrame c (XXI) wold yield semi-synthetic proteins. Studies on these semi-synthetic proteins would then give information about cytochrane c, which functions as an electron-transport, protein in the cells for the reduction of oxygen to water and the synthesis of adenosine triphosphate. Specifically, this information would be useful in detemining the mechanism of oxidation-reduction reactions , of cytochrame c and in understanding the structure-function relationships in the molecule. In the solid phase method applied in the synthesis of each peptide, the amino acid (104) which contains the free carboxyl group of the peptide has been attached to a polimer, known as the solid support, by forming a covalent bond between this carboxyl group and the polimer; and then all the other mino acids (103-66) have been added one at a time in a stepwise manner to this amino acid on the polimer. After the completion of addition, the free peptide has been released into solution by cleavage of the covalent bond between the peptide chain and the polimer. Finally, the peptide, obtahed in the solid form by lyophilization of the solution, has been purified by gel chromatography.Item Poli-2-vinilfuran'ın organik reaksiyonları(Thesis (Assoc. Prof.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 1980., 1980.) Küsefoğlu, Selim.The known and varied organic chemistry o f the furan ring has been used t o successfully transform poly-2-vinyl furan (PZVF) to a number of new polymeric systems. The Diels Alder adduct o f P2VF with maleicanhidride (3), the cross linking product of P2VF with asetone (7); the 2 - 4 dinitroph,enylhydrazine derivative of the acid hydrolysis product of P2VF (6) and the 5-aldehyde (8), 5-bromide (9) and 5-sulfonat (10) derivatives of P2VF have been synthesized and characterized using spectral and chemical techniques. The spectral and chemical properties o f the starting material P2VF which were not available in the literature have also been determined. Each o f the above syntheses involved the limitations and difficulties inherent in polymer reactions which had to be eliminated or minimized by judicial use of synthesis techniques. Although the physical propertiies o f the newly synthesized polymers lies outside the scope of this work, especially the P2VF maleican hidrite Diels-Alder adduct (3) and P2VF - asetone cross-linking product (7) deserve careful physical tests for further characterization.Item Metil radikallerinin tetrametilsilan ile fotoliz reaksiyonunun incelenmesi(Thesis (Assoc. Prof.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 1982., 1982.) Arıcan, Haluk.Bu çalışmada, metil radikalleri ile tetrametil silanda bulunan C-H bağlarının koparılma reaksiyonu incelenmiştir. Metil radikal kaynağı olarak aseton kullanılmıştır. Bugune kadar literatürde geçen metil radikallerinin tetrametilsilanla olan reaksiyonlarında radikal kaynağı olarak azometan kullanılmıştır. Aseton metil radikal kaynağı olarak ilk kez uygulanmış ve fotoliz reaksiyonunun sonunda elde edilen Arrhenius parametreleri benzeri reaksiyonlarınkilerle derinlenesine karşılaştırılmıştır. Ayrıca ürün analiz yöntemi olarak sisteme bir vanayla dogrudan baglı alev'iyon dedektörlü gaz kramatografisi kullanılmıştır. Bu yöntemle ürün analizi radikal sistemleri için ilk defa gerçekleştirilmiştir. Literatürde bulunan metilradikalleri ile tetra metilsilan (TMS) arasindaki Arrhecius parametreleri alınmiş ve en iyi deger hesap edilmiştir. Bu hesaplamayla elde edilen parametreler (log A = 11.41; E = 41.46 kjmnol -1) bu çalışma neticesinde doğan Arrhenius parametrelerinle (log A = 11.83; E = 44.65 kjmol-1) karşılaştırılmıştır. Bu karşılaştırma neticesinde de bulunan degerlerin digerleriyle iyi bir uyum içinde oldugu görülmüştür. Ayrıca bu kıyaslamayla yetinilmeyip, metil radikallerinden elde edilen degerler, CD3. CF3, CH2F, CHFJ, C H- ve C F 2 5 2F 5 radikallerinin tetra metil silanla olan reaksiyonlarının neticesi olan parametrelerle karşılaştırılmış ve radikal reaktivitelerine göre sıralandırılmıştır.Item Euphorbia larica, euphorbia virgata, euphorbia chamaesyce ve euphorbia magalantha bitkilerinin flavonoidleri(Thesis (Assoc. Prof.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 1982., 1982.) Halfon, Belkıs.