N-(methoxycarbonyl)-trans-4-hydroxy-L-proline methyl ester → N-(methoxycarbonyl)-trans-4-hydroxy-D-proline methyl ester

Participants

Reaction Steps

A 5.0 mL aqueous solution containing 51 mM N-(methoxycarbonyl)-trans-4-hydroxy-L-proline methyl ester and 51 mM N-(methoxycarbonyl)-cis-4-hydroxy-D-proline methyl ester in 0.100M potassium phosphate (pH 7.0) was mixed with 50 mg/mL of Candida antartica lipase fraction B at 25° C. The reaction was analyzed by removal of a 0.200 mL sample and mixing with an equivalent volume of 0.100M propionic acid (HPLC internal standard) in water. The resulting solution was filtered through a 10K molecular weight cut-off filter to remove the enzyme and the filtrate analyzed by high pressure liquid chromatography on a HPX-87H column (Bio-Rad, 30 cm×7.8 mm) to determine the percent conversion of each isomer of the diastereomeric mixture, and the diastereomeric excess of the N-(methoxycarbonyl)-trans-4-hydroxy-D-proline methyl ester. After 24 h, a 93% diastereomeric excess of N-(methoxycarbonyl)-trans-4-hydroxy-D-proline methyl ester was obtained at 57% conversion of the diastereomeric mixture (3.0% N-(methoxycarbonyl)-cis-4-hydroxy-L-proline methyl ester and 82.7% N-(methoxycarbonyl)-trans-4-hydroxy-D-proline methyl ester remained).

Provenance & Evidence