Novel bioconversion reactions for the syntheses of a-hydroxy ketones

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Kimya Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2009

Öğrenci: PERUZE AYHAN

Danışman: PINAR ÇALIK

Özet:

The objective of the study presented here was to develop either enzymatic or whole cell mediated green procedures for the syntheses of a-hydroxy ketones. Production of optically active synthons is crucial for the preparation of fine chemicals. Enzymes and whole-cell biocatalysts have proven to be excellent vehicles with their chiral nature for the biotransformations. Under the light of this discussion, firstly benzaldehyde lyase [BAL, (EC 4.1.2.38)] was used in novel C-C bond formation reactions to obtain interesting and biologically important precursors; 2-Hydroxy-1-arylethan-1-ones and functionalized aliphatic acyloin derivatives. All the compounds were obtained with high yields and in the case of aliphatic acyloin derivatives with high enantiomeric excesses (ee’s). Another strategy was to use whole cell biocatalysis. A.flavus 200120 was found to be a promising biocatalyst with the ability to catalyze a broad range of reactions; reduction, hydrolysis and deracemization, while another fungus; A. oryzae 5048 was utilized in bioreduction reactions of benzil and its derivatives. Each reaction was investigated, optimized and thus enhanced via medium design. Products were obtained with high yields and ee’s. To sum up, in this study novel efficient green procedures were developed to synthesize various ahydroxy ketones with high yield and stereoselectivity. These newly established methods present promising alternatives to classical chemical methodologies.