1-(1,1-Dimethylethyl) 4-(phenylmethyl) (2S)-1,2,4-piperazinetricarboxylate → (2S)-1-[(tert-butoxy)carbonyl]piperazine-2-carboxylic acid
Reaction equation
C(OC([N:11]1[CH2:16][CH2:15][N:14]([C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18])[C@H:13]([C:24]([OH:26])=[O:25])[CH2:12]1)=O)C1C=CC=CC=1.[H][H]>CO>[C:20]([O:19][C:17]([N:14]1[CH2:15][CH2:16][NH:11][CH2:12][C@H:13]1[C:24]([OH:26])=[O:25])=[O:18])([CH3:23])([CH3:21])[CH3:22]Participants
4
Procedure
A solution of 4.00 g (10.98 mmole) of (S)-4-(benzyloxycarbonyl)-1-(tert-butyloxycarbonyl)-piperazine-2-carboxylic acid in 40 ml of methanol was hydrogenated over 1.0 g of 10% pd/c with rocking at 25° under 40 psi of hydrogen for 16 hr. The mixture was filtered and the cake was washed with a mixture of 100 ml of dichloromethane, 50 ml of methanol and 1.0 g of diisopropylethyl amine. Concentration in vacuo followed by Pumping in vacuo for 2 hr left 2.39 g (95%) of white solid which was homogeneous by tlc (silica gel, 1:1:1:1 ethyl acetate:n-butanol:acetic acid:water, Rf =0.70).