Trifluoroacetic acid → 4-Cbz-aminopiperidine

Participants

Reaction Steps

To a solution of 4-benzyloxycarbonylamino-piperidine-1-carboxylic acid tert-butyl ester (20.4 g, crude from previous step) in dichloromethane (100 mL) at 23° C. was added trifluoroacetic acid (40 mL). After stirring for 45 min the reaction mixture was concentrated. The residue was dissolved in water (100 mL) then basified to pH 11 via addition of solid potassium carbonate. The resulting solution was extracted with dichloromethane (2×150 mL). The organic extracts were extremely cloudy; they were dried (Na2SO4), filtered and concentrated. The residue was dissolved/suspended in chloroform (70 mL) and the observed particulates were removed via filtration through a glass frit. The solution was concentrated to give 15 g of brown oil. This material was used without purification in the subsequent step.

Provenance & Evidence