(+-)-Penicillamine → 2-Amino-3-methyl-3-((2,4,6-trimethoxyphenyl)methylthio)butanoic acid

Participants

Reaction Conditions

Reaction Steps

A suspension of 2-amino-3-methyl-3-sulfanylbutanoic acid (D-penicillamine) (5.0 g, 34 mmol) in CH2Cl2 (150 mL) was cooled to 0° C. Trifluoroacetic acid (54 mL, 703 mmol) was added dropwise over a period of 5 min. Then 2,4,6-trimethoxy-benzyl alcohol (6.64 g, 34 mmol) in CH2Cl2 (137 mL) was added dropwise at 0° C. with stirring. Stirring was continued for 1 hour at 0° C. and then for 2 hours at room temperature. The solvent was removed in vacuo and the residue was dried under high vacuum for 3 hours. The crude red solid was recrystallized from 1:1:1 CH2Cl2/MeOH/EtOAc to give the title compound (10.5 g, 95%) as a white solid. 1H-NMR (300 MHz, CDCl3) δ 6.10 (s, 2H), 3.84 (s, 6H), 3.76 (s, 3H), 3.40-4.10 (m, 3H), 1.69 (s, 3H), 1.23 (s, 3H); mass spectrum (API-TIS) m/z 330 (MH+).

Provenance & Evidence