ORGN 91 |
| Many efforts have been recently made to develop enzyme catalysts for the enantioselective reduction of ketones and varied level of success have been achieved. However, enzymatic reduction of bucky ketones such as aromatic alpha-ketoesters is much less successful than that of their small counterparts. Because hydroxysteroid dehydyrogenases takes bucky native substrates, we reasoned that this family of alcohol dehydrogenases might be promising in the reduction of bucky ketones. we successfully cloned a 7-hydroxysteroid dehydyrogenase gene from Bacteroides fragilis. The encoding protein was expressed in E. coli and purified from the cell-free extract. The purified enzyme was found to be active toward a series of aromatic alpha-ketoesters. This alcohol dehydrogenase was also active toward alpha-ketoesters with bucky groups such as tert-butyl and cyclohexyl groups at the other side of carbonyl group. The effects of substituents at the benzyl ring of aromatic alpha-ketoesters on the activity and enantioselectivity were studied. This enzyme was then applied to the synthesis of a few aromatic a-hydroxy carboxylic acid esters of pharmaceutical importance. |
|
Asymmetric Reactions and Syntheses, Physical Organic Chemistry, Combinatorial Chemistry, Total Synthesis
8:00 PM-10:00 PM, Sunday, 26 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Organic Chemistry |