4-Fluorobenzenesulfonyl chloride → (R)-2-(4-fluoro-benzenesulfonylamino)-4-methyl-pentanoic acid

Reaction equation

[F:1][C:2]1[CH:7]=[CH:6][C:5]([S:8](Cl)(=[O:10])=[O:9])=[CH:4][CH:3]=1.[NH2:12][C@H:13]([CH2:17][CH:18]([CH3:20])[CH3:19])[C:14]([OH:16])=[O:15].C(=O)([O-])[O-].[Na+].[Na+]>O>[F:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([NH:12][C@H:13]([CH2:17][CH:18]([CH3:20])[CH3:19])[C:14]([OH:16])=[O:15])(=[O:10])=[O:9])=[CH:4][CH:3]=1

Participants

Procedure

A mixture of 4-fluoro-benzenesulfonyl chloride (1.65 g, 0.00848 mol), (R)-2-amino-4-methyl-pentanoic acid (1.233 g, 0.009398 mol), and sodium carbonate (1.91 g, 0.0180 mol) in water (15 mL) was stirred at room temperature for 5 days. The solution was filtered, and the filtrate was acidified with concentrated hydrochloric acid to pH=4. The mixture was extracted with ethyl acetate. The extract was washed with saturated sodium chloride, dried (MgSO4), and rotary evaporated to a yellow oil. The oil was chromatographed on silica gel (320 g, 230-400 mesh) eluting with dichloromethane-methanol (10:1, 10×300 mL). Fractions containing product were combined and rotary evaporated to give a pale yellow oil. The oil was dried in vacuo; yield 1.44 g (59%).