Trifluoroacetic acid → HCID 21948309, compound

Participants

Reaction Steps

Trifluoroacetic acid (100 ml) was added to a solution of 4-benzyloxycarbonyl-1-[1,4-bis(tert-butoxycarbonyl)-4-piperidylmethyl]-2-piperazinone (38.8 g) obtained in Reference Example 1 in toluene (100 ml), the mixture was stirred at room temperature for 1 hour, and concentrated under reduced pressure. Then, di-tert-butyl dicarbonate (17.6 ml) was added to a mixture of the residue, sodium carbonate (38.7 g), water (300 ml) and ethyl acetate (300 ml) at room temperature while stirring, and the mixture was stirred at room temperature for 1 hour. The reaction mixture was separated into layers, the aqueous layer was adjusted to pH 3 with 1N hydrochloric acid, and extracted with ethyl acetate. The ethyl acetate layer was dried with magnesium sulfate, and concentrated under reduced pressure, and the residue was purified by silica gel chromatography (ethyl acetate:methanol=10/1) to obtain the title compound (29 g) as yellow powders.

Provenance & Evidence