L-Serine, methyl ester, hydrochloride (1:1) → methyl (2S)-2-[(3,4-difluorophenyl)sulfonylamino]-3-hydroxy-propanoate

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Reaction Steps

A suspension of L-serine-methyl ester hydrochloride (1.5 g, 9.5 mmol) in CH2Cl2 (70 mL) was added with TEA (1.1 mol eq, 1.45 mL) and the mixture was stirred at r.t. for 10 minutes. Then 3,4-difluorobenzensulfonyl chloride (1 mol eq, 2.0 g) and additional TEA (1.1 mol eq) were added and the solution hated at 60° C. overnight. The solvent was removed under reduced pressure, water was added to the residue (100 mL) and the aqueous phase extracted with EtOAc (3×40 mL). The recombined organic phases were dried over Na2SO4 and evaporated to reduced pressure. The residue was recrystallized from ethylic ether to afford 2G as a pale orange solid (2.85 g, 94% yield). 1HNMR (DMSO, 200 MHz) δ 3.45 (s, 3H), 3.54 (m, 2H), 3.95 (m, 1H), 5.01 (t, 1H), 7.66 (m, 2H), 7.88 (m, 1H), 8.46 (d, 1H, J=8).

Provenance & Evidence