| 17285287 |
Salinas Y, Oliart RM, Ramirez-Lepe M, Navarro-Ocana A, Valerio-Alfaro G: Synthesis of chiral alpha-hydroxy amides by two sequential enzymatic catalyzed reactions. Appl Microbiol Biotechnol. 2007 May;75(2):297-302. Epub 2007 Feb 7.
Enantiomerically pure alpha-hydroxy amides have been prepared from the corresponding alpha-oxo esters by the use of a double sequence reaction involving in a first step the highly enantioselective Saccharomyces cerevisiae bioreduction and then in a second step, the resulting alpha-hydroxy esters followed a non-enantiospecific lipase catalyzed aminolysis with n-butylamine reaction. In the first non-organic solvent process, the moistened baker's yeast reduced seven alpha-oxo esters with high conversions degree (93% for one substrate and > 99% for the others) and high enantioselectivities [> 99% for all the substrates except for ketopantoyl lactone, which gave 88% of enantiomeric excess (ee)]. At the same way, the isolated resulting chiral alpha-hydroxy esters were subjected to the second Candida antarctica lipase fraction B (CAL-B) catalyzed aminolysis in dioxane conducting to the corresponding chiral alpha-hydroxy amides with high conversions degree, between 88 and 99%. Both processes were carried out at 28-30 degrees C. |
82(1,1,1,2) |