Acetic Anhydride → (S)-N-(3-Chloro-2-hydroxypropyl)acetamide

Beteiligte Stoffe

Reaktionsschritte

Triethylamine (10.5 ml, 75.3 mmol, 1.11 eq) is added to a slurry of (S)-1-amino-3-chloro-2-propanol hydrochloride (V, EXAMPLE 1, 9,938 g, 68.059 mmol) in THF (80 ml) at −40° and the mixture stirred for 5 min at −40°. Acetic anhydride (6.78 ml, 71.86 mmol, 1.056 eq) is then added at −40° and the mixture allowed to warm to 20-25° over 1.5 hrs. The precipitate is removed by filtration with reduced pressure and washed with THF. The filtrate is treated with magnesol (5.69 g), which is removed by filtration with reduced pressure and washed with THF (2×60 ml). The filtrate is then concentrated under reduced pressure. The concentrate is purified by flash chromatography (silica gel; eluting with a gradient of 75-100% ethyl acetate/cyclohexane) to give the title compound, NMR (CDCl3) 2.03, 3.32, 3.50-3.57, 3.55, 3.91-4.13, 5.01 and 7.09 δ; CMR (CDCl3) 23.00, 43.31, 46.52, 70.65 and 172.40 δ; MS (CI, NH3), M/Z (relative intensity), 171 (41.6), 169 (100), 154 (22.4), 152 (48.1); [α]25D=−7.44 (c=1.00, H2O).

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