Methanol → 2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)-5-chlorobenzoic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-(4-chloro-2-cyano-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (0.6 g, 1.86 mmol) in methanol (4.0 mL) was added 1.0 N NaOH (4.0 mL, 4.0 mmol) and the resulting mixture was heated to reflux at 80° C. for 36 h. Additional 1.0 N NaOH (2.0 ml, 2.0 mmol) was added to the reaction mixture and refluxed further for 18 hrs. The reaction mixture was concentrated and acidified to pH 4.0-5.0 using 1.0 N HCl and extracted with chloroform (5×). The combined organics were dried over sodium sulfate, concentrated and dried in vacuo overnight. The product contained approximately 20% amide and was separated after esterification in the next step. ESI-MS m/z: 341 (M+1), UV retention time: 2.33 min.

Provenance & Evidence