Water → (S)-alpha-[(t-butylsulphonyl)methyl]hydrocinnamic acid

Beteiligte Stoffe

Reaktionsschritte

A solution of 79 g (0.25 mol) of ethyl (RS)-α-[(tert-butylsulfonyl)methyl]hydrocinnamate in 105 ml of dimethyl sulfoxide was added dropwise while stirring vigorously to 6.2 l of water at 30° C. The pH value was adjusted to 7.5 with 0.1N sodium hydroxide solution. The hydrolysis was started by the addition of 1.05 g of α-chymotrypsin. The pH value was held constant at 7.5 using automatic titration by dosing-in 0.043N calcium hydroxide solution of 30° C. After a consumption of 2.67 l of 0.043N calcium hydroxide solution (after 19.5 hours), the reaction mixture was extracted three times with 2 l of ethyl acetate. The aqueous phase was acidified to pH 2.5 with 5% hydrochloric acid and extracted twice with 2 l of ethyl acetate. The organic phases were filtered over DICALITE Speedex, combined and dried over magnesium sulfate. After evaporating the solvent and drying the residue in a high vacuum, there were obtained 35 g (0.12 mol, 48.3%, 96.9% of theory) of (S)-α-[(tert-butylsulfonyl)methyl]hydrocinnamic acid in the form of white crystals, which had an enantiomeric excess of >98%. In order to determine the purity by gas chromatography, the compound obtained was silylated and had a purity of >99%.

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