Acetonitrile → Trifluoroacetic acid

Participants

Reaction Steps

2-Amino-4-[1-(carboxymethyl-carbamoyl)-2-(2,3-dioxo-3-piperidin-1-yl-propylsulfanyl)-ethylcarbamoyl]-butyric acid as its TFA salt (400 mg, 0.696 mol) was dissolved in 8 mL of water to which was added 1.3 eq. of solid NH2OH.HCl at 0° C. and the homogeneous solution was left standing over-night. LC/MS indicated that the reaction was incomplete. An additional 1 eq. of NH2OH.HCl was added at room temperature and the homogeneous solution was left standing overnight. LC/MS indicated complete conversion of the starting amide to the corresponding oxime. The aqueous mixture was then passed through reversed-phase C18 column using water and acetonitrile mixture as gradient eluent. The pure fractions were pooled, concentrated under vacuum at room temperature to one fourth of the volume and finally freeze-dried to obtain 2-amino-4-[1-(carboxymethyl-carbamoyl)-2-(2-hydroxyimino-3-oxo-3-piperidin-1-yl-propylsulfanyl)-ethylcarbamoyl]-butyric acid as its TFA salt (390 mg, 95.1%).

Provenance & Evidence