Hydrochloric Acid → 4-Carbobenzyloxy-l-(4-chloro-2-nitrophenyl)piperazine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-carbobenzyloxypiperazine-2-carboxylic acid, copper chelate in 750 ml water was added ethylenediaminetetracetic acid, disodium salt, dihydrate (7.9 g, 21 mmol) and the blue mixture was heated to 80° C. for 3 h. The reaction mixture was cooled to rt and concentrated to dryness. The blue residue was dissolved in 100 ml DMSO. 2,4-dichloronitrobenzene (6.66 g, 35 mmol) and triethyl amine (20 ml, 143 mmol) were added and the solution was heated to 60° C. for 16 h. The dark reaction mixture was cooled to rt. Concentrated HCl was added to pH=3. The solution was then diluted with 500 ml water and the aqueous layer was extracted with ethyl acetate. The combined organics were washed with water, dried over MgSO4 and concentrated to afford 4-carbobenzyloxy-l-(4-chloro-2-nitrophenyl)piperazine-2-carboxylic acid as a yellow residue used directly in the next step.

Provenance & Evidence