Trifluoromethanesulfonic acid → CID 140386399

Participants

Reaction Steps

880 mg of (2S,4S)-4-(4-methoxybenzylthio)-2-[4-(4-nitrobenzyloxycarbonylamidino)piperazin-1-ylcarbonyl]-1-(4-nitrobenzyloxycarbonyl)pyrrolidine [prepared as described in step (d) above] were dissolved in a mixture of 4.4 ml of trifluoroacetic acid and 0.88 ml of anisole, and then 160 μl of trifluoromethanesulfonic acid were added dropwise to this solution, whilst stirring and ice-cooling. The resulting mixture was then stirred at room temperature for 3 hours, after which it was concentrated by evaporation under reduced pressure. The resulting residue was washed three times with diethyl ether, and the powder thus formed was dried to obtain 918 mg of the title compound, as a powder.

Provenance & Evidence