Boron tribromide → Metyrosine

Participants

Reaction Steps

tert-Butyl 2-amino-3-(4-methoxyphenyl)-2-methylpropanoate (0.30 g, 1.13 mmol) was dissolved in CH2Cl2 (3 mL) and BBr3 (0.85 g, 3.39 mmol, 3 equiv) was added at room temperature. The reaction mixture was stirred for 1.5 h and treated with a NaHCO3 solution to a basic pH. The aqueous phase was isolated. Solid started to precipitate in the aqueous phase in 30 min. Solid was filtered in 16 h and was washed on a filter with CH2Cl2 (2 mL) and water (2 mL). The solid was air-dried to afford metyrosine [0.10 g; 45.4%] as a white solid [HPLC 80.7% (Metyrosine; AUC; tR=2.32 & 2.57]. 1H NMR (500 MHz, TFA-d): δ 8.60 (d, J=8.7 Hz, 2H, Ar), 8.39 (d, J=8.7 Hz, 2H, Ar), 4.91 (d, J=15.0 Hz, 1H, CH2), 4.67 (d, J=15.0 Hz, 1H, CH2), 3.30 (s, 3H, CH3). Optical rotation (α30D, c=1.080, 1=10 mm, NaOAc/CuSO4/H2O/AcOH)+148.1.

Provenance & Evidence