Hydrochloric Acid → (2S)-tert-butoxy(4-iodo-2-methyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-b]pyridin-3-yl)acetic acid

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Reaction Conditions

Reaction Steps

To a solution of (4R)-4-benzyl-3-[(2S)-2-tert-butoxy-2-(4-iodo-2-methyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-b]pyridin-3-yl)acetyl]-1,3-oxazolidin-2-one (Preparation 13B, 21.36 g, 34.53 mmol) in tetrahydrofuran (400 mL) and water (130 mL) at 0° C. was added dropwise a solution of lithium hydroxide hydrate (3.04 g, 72.52 mmol) and hydrogen peroxide (27% aqueous, 16.4 mL, 145.04 mmol). The resulting solution was stirred at 0° C. for 15 minutes, then for 2 hours at room temperature. A saturated solution of sodium sulphite (500 mL) was added followed by water (500 mL), and the mixture stirred for 15 minutes. The mixture was acidified to pH 4 by the addition of 6 M hydrochloric acid. The mixture was extracted with dichloromethane (4×500 mL). The combined organic layers were dried over MgSO4 and concentrated in vacuo. The resulting white solid was crystallised from methylated spirits (150 mL) with heating at reflux for 5 minutes. The mixture was allowed to cool to room temperature overnight. The resulting solid was collected by filtration and washed with cold methylated spirits and dried in vacuo to give the title compound as a white solid, 10.25 g, in a 65% yield.

Provenance & Evidence