| Popis: |
Several lipases were tested for the enantiomerically selective acetylation of racemic 1-[6-(1-hydroxyethyl)-pyridin-2-yl]ethanone rac - 2 to yield alcohol ( S )- 2 and acetate ( R )- 3 . Acetylation of a diastereomeric mixture of racemic and meso -2,6-bis(1-hydroxy-ethyl)pyridine, rac/meso - 4 , with the most selective Novozym 435 lipase in vinyl acetate resulted in a mixture of enantiopure diol ( S , S )- 4 , monoacetate ( R , S )- 5 and diacetate ( R , R )- 6 . Hydrolysis of the mixture of racemic and meso -2,6-bis(1-acetoxyethyl)pyridine rac/meso - 6 by the same enzyme gave the pure enantiomers of diol ( R , R )- 4 , monoacetate ( S , R )- 5 and diacetate ( S , S )- 6 . Using further chemical and enzymatic steps alcohol ( R )- 2 , acetate ( S )- 3 , ( S , S )- and ( R , R )-monoacetates ( S , S )- 5 and ( R , R )- 5 , meso - 4 and its acetate meso - 6 were also prepared and characterized. |
Full Text from ScienceDirect