Dynamic kinetic resolution of phenylglycine esters via lipase-catalysed ammonolysis
1999; Elsevier BV; Volume: 10; Issue: 9 Linguagem: Inglês
10.1016/s0957-4166(99)00143-3
ISSN1362-511X
AutoresMargreth A. Wegman, Michiel A. P. J. Hacking, J. Rops, Pedro C. Pereira, Fred van Rantwijk, Roger A. Sheldon,
Tópico(s)Analytical Chemistry and Chromatography
ResumoAmmonolysis of d,l-phenylglycine methyl ester catalysed by Novozym 435 at 40°C in tert-butyl alcohol gave d-phenylglycine amide in 78% ee at 46% conversion, corresponding to an enantiomeric ratio (E) of 16. Lowering the temperature improved the enantioselectivity (E=52 at −20°C). Combination of ammonolysis with pyridoxal-catalysed in situ racemisation of the unconverted ester (dynamic kinetic resolution), at −20°C, gave d-phenylglycine amide with 88% ee at 85% conversion. The amide racemised much slower than the ester at this low temperature.
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