Hydrochloric Acid → (S)-2-Ethoxy-3-[2-methyl-4-(5-methyl-2-o-tolyl-oxazol-4-ylmethoxy)-phenyl]-propionic acid

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Reaction Steps

To a solution of (S)-2-ethoxy-3-[2-methyl-4-(5-methyl-2-o-tolyl-oxazol-4-ylmethoxy)-phenyl]-propionic acid methyl ester (100 mg, 0.24 mmol) in THF/methanol 2/1 (1.5 ml) was added a 1 N aqueous LiOH solution (1.4 ml, 1.4 mmol). The reaction mixture was stirred for 1.5 h at ambient temperature, neutralized with 1 N aqueous HCl solution under ice cooling and concentrated under reduced pressure. The residue was dissolved in 1 N HCl/ice water 1/1 and ethyl acetate, the layers were separated and the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with ice water/brine 1/1, dried over sodium sulfate and the solvent was evaporated in vacuo to give the title compound (88 mg, 0.21 mmol, 91%) as off-white solid, which was crystalized from dichloromethane/hexane to afford colorless crystals. According to chiral HPLC of the corresponding methyl ester (Chiralcel-ODH), the enantiomeric excess amounts to 98.6%.

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