Sulfamic Acid → 2-(4-(Tert-butoxycarbonyl)piperazin-1-yl)benzoic acid

Participants

Reaction Conditions

Reaction Steps

An alternative method for preparing this intermediate is as follows. 4-(2-Formyl-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (0.50 g, 1.72 mmol) is dissolved in 80 mL of dioxane and 20 mL of H2O. The mixture is cooled to 4° C. To this is added sulfamic acid (1.36 g, 14.00 mmol) in one portion. The mixture is stirred for an additional 30 min. To this is added 3 mL of a solution of NaClO2 (0.343 g, 3.80 mmol) in a dropwise manner. The reaction is quenched reaction with addition of 50 mL of H2O and 50 mL of brine. The mixture is extracted with 3×100 mL of CH2Cl2. The organic phase is washed with 2×50 mL of brine, dried (MgSO4), filtered and concentrated to give 500 mg of 4-(2-carboxy-phenyl)-piperazine-1-carboxylic acid tert-butyl ester, 95% yield.

Provenance & Evidence