Imidazole → 2-(t-Butoxycarbonylamino)-3-(t-butyldiphenylsiloxy)propanol

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Reaction Steps

At room temperature, imidazole (6.43 g) was added to a solution of N-(t-butoxycarbonyl)-L-serine methyl ester (13.8 g) in N,N-dimethylformamide (140 ml), followed by the addition of t-butyldiphenylsilyl chloride (19.7 ml) at 0° C. The resulting mixture was stirred at room temperature for 39 hours. Ethyl acetate (200 ml) and water (600 ml) were added to the reaction mixture to cause separation. The water layer was extracted with ethyl acetate (100 ml). The organic layers were combined, washed with saturated aqueous NaCl solution (100 ml), dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue thus obtained was dissolved in tetrahydrofuran (100 ml) and methanol (100 ml) without purification, followed by the addition of sodium borohydride (7.20 g) in portions at 0° C. After stirring at 0° C. for 2 hours and then at room temperature for 1 hour, ethyl acetate (100 ml), an aqueous saturated solution of ammonium chloride (300 ml) and water (300 ml) were added to the reaction mixture to cause separation. The water layer was extracted with ethyl acetate (100 ml). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue thus obtained was purified by chromatography on a silica gel column (500 g of silica gel, hexane:ethyl acetate=10:1˜1:1), whereby the title compound (24.9 g) was obtained as a white solid.

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