1-(1,1-Dimethylethyl) 4-(phenylmethyl) (2S)-1,2,4-piperazinetricarboxylate → (2S)-1-[(tert-butoxy)carbonyl]piperazine-2-carboxylic acid

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Reaction Steps

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).

Provenance & Evidence