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Báo cáo vật lý: "Enzymatic Reduction of Ketones to Optically Active Secondary Alcohols"

Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí khoa học vật lý quốc tế đề tài: Enzymatic Reduction of Ketones to Optically Active Secondary Alcohols | Journal of Physical Science Vol. 19 2 1-5 2008 1 Enzymatic Reduction of Ketones to Optically Active Secondary Alcohols R.A. Bawa F. Ajjabou and E. Shalfooh Department of Chemistry Faculty of Science University of 7th October P.O. Box 875 Misurata Libya Corresponding author ramadanali70@yahoo.com Abstract A number of unsymmetrical ketones such as ethyl acetoacetate 4-hydroxy acetophenone 4-methylacetophenone 4-acetylpyridine and pyruvic acid were reduced to the corresponding optically active secondary alcohols. The reduction reaction was monitored by Uv-Vis spectrophotometer and a complete conversion was observed in all cases within 24 to 48 h. The procedure was optimized in order to accelerate the reduction process and reduce the reaction time. This was achieved by increasing the temperature to 40 C. Keywords ketones secondary alcohols enzymatic reduction 1. INTRODUCTION Enantioselective reduction of ketones to optically active secondary alcohols is one of the most interesting areas of research for a number of research groups.1-5 Enzymes have been widely used in converting ketones to the corresponding optically active secondary alcohols. This technique has shown good to excellent levels of enantiomeric excess.1-3 An alcohol dehydrogenase from the hyperthermophilic archaeon Pyrococcus furiosus has been used to catalyze the reduction of a variety of aliphatic ketones aryl ketones a- and ft-ketoesters. Aryl ketones a- and -ketoesters that contain phenyl substituents were reported to be reduced to the corresponding enantiomerically pure chiral alcohols whereas the reduction of aliphatic ketones gave a moderate levels of enantioselectivity. This indicates that the presence of a phenyl group adjacent to the carbonyl group could be an important factor for obtaining high levels of enantioselectivity.1 Voss et al. used a practical approach for inverting R -alcohols to the .S - counterparts via an oxidation reduction biochemical process using lyophilised cells of .