Kinetic resolution of leishmanicidal meta and para (±)-2-[Hydroxy(nitrophenyl)methyl]acrylonitrile catalyzed by CALB: In vitro evaluations of separated meta (R), (S) and (R/S) adducts

The acyl derivatives enantiomers of the Morita–Baylis–Hillman adduct (±)-2-[Hydroxy(m-nitrophenyl)methyl]acrylonitrile (1) and (±)-2-[Hydroxy(p-nitrophenyl)methyl]acrylonitrile (2) were efficiently separated by kinetic resolution catalyzed by lipase B from Candida antarctica giving (R)-1 and (R)-2 in very high enantioselectivity (>99% e.e.). These absolute configurations were elucidated by Mosher methodology. The opposite enantiomers (S)-1 and (S)-2 (86.8% e.e. and 97.5% e.e., respectively) were prepared through the hydrolysis of the corresponding unreacted esters. Antileishmanial activities for the adduct (±)-1 and their separated enantiomers (R)-1 and (S)-1 were evaluated for the first time. The results showed that the racemic compound is more potent than each separated enantiomers.