Dicyclohexylcarbodiimide → 13-(S)-[[(9H-Fluoren-9-yl)methoxycarbonyl]amino]-3-(R)-methyl-12-oxo-14-(phenylmethoxy)-6-(phenylmethyl)-2,6,11-triazatetradecanoic acid, 1,1-dimethylethyl ester

Participants

Reaction Conditions

Reaction Steps

1.71 g (4.1.10-3 mol) of N-[(9H-fluoren-9-yl)methoxycarbonyl]-O-phenylmethyl-(L)-serine are dissolved in 60 ml of dichloromethane. The solution is cooled to 0° C. and a solution of 0.55 g (4.10-3 mol) of HOBT and 1.54 g (7.5.10-3 mol) of DCC in 20 ml of dichloromethane is added. The mixture is stirred for 0.5 hour, 1.30 g (3.72.10-3 mol) of N-[3-[(4-aminobutyl)(phenylmethyl)amino]-1-(R)-methylpropyl]carbamic acid, 1, 1-dimethylethyl ester are then added and the reaction mixture is stirred at room temperature for 16 hours. The solvent is removed under reduced pressure and the residue is purified by chromatography on silica gel using an ethyl acetate/methylcyclohexane mixture (1/1 v/v) and then pure ethyl acetate as the eluent to give 2.7 g of the expected product in the form of a white crystalline solid (yield=96%).

Provenance & Evidence