Hydrochloric Acid → Diphenylmethyl 3-(4-fluorophenyl)lactate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To 4-fluorophenylalanine (4.99 g, 27.2 mmol) was added a 0.5N aqueous solution of HCl (123 ml). The obtained mixture was cooled to 0° C. under cooling with ice and silver nitrite (5.6 g, 36.2 mmol) was further added thereto in several portions within 1 hour under vigorous stirring. Six hours thereafter, the obtained mixture was heated to room temperature and further stirred for 1 day. The silver chloride thus precipitated was removed out by filtration and the filtrate was extracted with diethyl ether (200 ml×4). The diethyl ether phase was dried over (MgSO4 was used). The diethyl ether phase filtered was concentrated under reduced pressure. Thus, a crude product (4.69 g) of 3-(4-fluorophenyl)lactic acid was obtained. Next, this crude product (4.69 g) was dissolved in dry dimethylformamide (80 ml) and cesium carbonate (8.58 g, 26.8 mmol) was added thereto. The mixture thus obtained was stirred at room temperature for 40 minutes and subsequently bromodiphenylmethane (11.8 g, 47.8 mmol) was added thereto. The resulting mixture was stirred at room temperature for a day and water (300 ml) was then added thereto. The mixture thus obtained was extracted with ethyl acetate (100 ml×3). Next, the organic phase was washed with a saturated aqueous solution of sodium hydrogencarbonate (100 ml) and a saturated aqueous sodium chloride (100 ml) and dried over magnesium sulfate. After filtering thereof, the residue (13.4 g), which was obtained by concentrating the filtrate under reduced pressure, was purified by silica gel column chromatography (hexane: ethyl acetate=90:10). As a result, the title compound (4.2 g, 44%) was obtained as white crystals.

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