dimethyl 3-methyl-L-aspartate → (2S)-2-amino-4-methoxy-3-methyl-4-oxobutanoic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of dimethyl 3-methyl-L-aspartate (Preparation 64, 23 g, 82.55 mmol), CuCO3.Cu(OH)2 (21.9 g, 99.05 mmol) in water (250 mL) was heated to 70° C. for 4 hours. The resulting precipitate was filtered and the filtrate cooled to 0° C. Ammonium sulfide (20% in water, 67.5 mL, 198 mmol) was added slowly ensuring the temperature did not rise above 5° C. The reaction was filtered through arbocel to remove the copper residues and the filtrate concentrated in vacuo. The residue was redissolved in MeOH and filtered through arbocel, with concentration of the filtrate to dryness to afford the title compound as an oil that was used directly in the next step.

Provenance & Evidence