4-Fluorobenzenesulfonyl chloride → (S)-3-(4-benzyloxy-phenyl)-2-(4-fluoro-benzenesulfonylamino)-propionic acid

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Reaction Steps

A mixture of (S)-2-amino-3-(4-benzyloxy-phenyl)-propionic acid (2.7 g, 0.010 mol), 4-fluoro-benzenesulfonyl chloride (2.0 g, 0.010 mol), and sodium carbonate (2.2 g, 0.020 mol) in a mixture of tetrahydrofuran (20 mL) and water (20 mL) was stirred at room temperature for 3 days. The reaction mixture was partitioned between ethyl acetate and 1 M hydrochloric acid. The organic layer was washed with saturated sodium chloride solution, dried (MgSO4), and rotary-evaporated under reduced pressure to give an oil. The oil was chromatographed on silica gel (445 g, 230-400 mesh) eluting with dichloromethane-methanol (20:1), and the fractions containing product were rotary-evaporated to give a solid. The solid was recrystallized from toluene to give the title compound as a light yellow solid; yield 0.22 g (5%), mp=138-139° C.

Provenance & Evidence