Hydrochloric Acid → 1-Acetamido-3-chloropropan-2-yl acetate

참여 물질

반응 단계

Acetic anhydride (13 ml) is added to a thin slurry of L+)-1-amino-3-chloro-2-propanol hydrochloride ((±)-V, EXAMPLE 5, 5.0110 g, 34.317 mmol) in pyridine (20 ml) while maintaining the temperature in the range of 20-50°. The mixture is stirred at 20-25° for 18 hours, then water (14 ml) is added with an exotherm to 65°. The mixture is concentrated under reduced pressure and water (50 ml) is added. The pH is adjusted to 0.89 with hydrochloric acid (37.7%, 1.467 g, 15.17 mmol, 0.442 eq) at 0°. The mixture is extracted with methylene chloride (4×50 ml), the extracts dried over sodium sulfate and concentrated under reduced pressure. Ethyl acetate (20 ml) and heptane (20 ml) are added, the mixture seeded, then heptane (40 ml) is added to the resultant slurry. The precipitate is collected by filtration with reduced pressure, washed with heptane and dried to give a the title compound, mp=68.0-69.50; TLC (silica gel; ethyl acetate, iodine char) Rf =0.39 (one spot); NMR 2.00, 2.21, 3.52, 3.62, 3.70, 5.10 and 6.33 δ; CMR 20.93, 23.10, 40.47, 43.53, 71.95, 170.45 and 170.71 δ; MS (CI, NH3) m/z (relative intensity) 213 (36), 211 (100), 196 (18) and 194 (53).

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