Resolution of N-(2-ethyl-6-methylphenyl)alanine via free and immobilized lipase from Pseudomonas cepacia

A biocatalytic approach for the production of (S)-N-(2-ethyl-6-methylphenyl)alanine, a key intermediate for (S)-Metolachlor, has been developed by the use of lipase-catalyzed hydrolytic kinetic resolution. Compared with other selected lipases, the lipase from Pseudomonas cepacia (PSL) gives good conversion (48.2%) and excellent enantioselectivity (E-value > 100) to obtain enantiomerically pure (R)-acid (99% e.e.p). Then, a simple second resolution procedure is used to prepare (S)-acid product from the remaining (S)-ester without any reduction in enantiomeric excess (98% e.e.p) using the lipase B from Candida antarctica (CAL-B). Subsequent PSL immobilized on mesoporous SBA-15 molecular sieve is studied. The resulting supported enzyme catalyst exhibits higher activity, stability as well as reusability, compared with free enzyme.