Sodium Hydroxide → (2S)-2-Ethoxy-3-(4-hydroxyphenyl)propanoic acid

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Reaction Steps

Ethyl (2R/S) (+/−) 2-ethoxy-3-(4-hydroxyphenyl)propanoate (5 g) was added to an aqueous 0.1 M phosphate buffer pH 7 (10 ml). 100 mg of the lyophilised esterase preparation from Aspergillus oryzae was added and the mixture was stirred for 18 hours at room temperature. During that time, the pH of the reaction mixture was kept constant at pH=6-8 by addition of NaOH. Most of the water was evaporated in vacuo. Methanol was added to the remaining slurry in order to stop the hydrolysis. The precipitate, which formed was filtered off and the methanol was evaporated in vacuo. The remaining oil was dissolved in water followed by extraction of unreacted ester with tert-butyl methyl ether (TBME) (eeester=87%, determined as in Example 2). The water phase was acidified to pH=3 and the acid extracted with TBME. After drying over Na2SO4 and evaporation of the TBME, 1.8 g (2S)-2-Ethoxy-3-(4-hydroxyphenyl)propanoic acid was obtained as an oil, which crystallized on standing (m.p.=105° C., eeacid=>99%, determined as in Example 2).

Provenance & Evidence