Diisopropylethylamine → 3-{[2-[2,6-Bis(isopropyl)phenoxycarbonyl]-benzoyl]amino}-propanoic Acid

Participants

Reaction Steps

To a solution containing (102) (2.1 g, 6.4 mmol) and beta-alanine tert-butyl ester hydrochloride (1.16 g, 6.4 mmol) in DMF (20 mL) was added diisopropylethylamine (2.4 mL, 13.7 mmol) followed by O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (2.5 g, 6.5 mmol). The resulting reaction mixture was stirred at room temperature for 14 h, diluted with ethyl acetate (100 mL), washed with 10% aqueous citric acid solution (5mL), followed by saturated aqueous NaHCO3 solution (50 mL) and brine (2×50 mL). The organic phase was dried over MgSO4 and concentrated in vacuo. The crude residue was dissolved in anhydrous dichloromethane (30 mL) and cooled to 0° C. before a solution of hydrochloric acid (10 mL, 4 N in dioxane) was added. The reaction was stirred for 1 h at 0° C. and 1 h at room temperature. The solvent was removed in vacuo and the crude residue was purified by preparative LC/MS to afford 0.85 g (38% yield over three steps) of the title compound (101). 1H NMR (400 MHz, CD3OD): δ 8.20 (dd, J=7.6, 0.8 Hz, 1H), 7.70-7.68 (m, 1H), 7.63-7.59 (m, 1H), 7.49 (dd, J=7.6, 0.8 Hz, 1H), 7.22-7.17 (m, 3H), 3.54 (t, J=7.2 Hz, 2H), 3.06-3.00 (m, 2H), 2.57 (t, J=6.8 Hz, 2H), 1.19 (d, J=6.8 Hz, 12H). MS (ESI) m/z 398.3 (M+H+).

Provenance & Evidence