4-Fluorobenzenesulfonyl chloride → methyl (2S)-2-[(4-fluorophenyl)sulfonylamino]-3-hydroxy-propanoate

Participants

Reaction Steps

A suspension of L-serine-methyl ester hydrochloride 1 (5 g, 32.13 mmol) in CH2Cl2 (100 mL) was added with TEA (1.1 mol eq, 4.9 mL) and the mixture stirred at r.t. for 10 minutes. Then 4-fluorobenzensulfonyl chloride (1 mol eq, 6.26 g) and additional TEA (1.1 mol eq) were added and the resulting solution heated at 50° C. for 6 h. The solvent was removed under reduced pressure, water was added to the residue (100 mL) and the aqueous phase finally extracted with EtOAc (3×40 mL). The combined organic phases were dried over Na2SO4 and evaporated under reduced pressure. The residue was recrystallized from ethyl ether to afford 2A as white solid (7.10 g, 80% yield). 1HNMR (DMSO, 200 MHz) δ 3.48 (s, 3H), 3.53 (m, 2H), 3.86 (t, 1H), 5.07 (t, 1H), 7.41 (m, 2H), 7.83 (m, 2H), 8.33 (bs, 1H).

Provenance & Evidence