4-Hydroxybenzoic Acid → Tert-butyl 4-{4-[(4-hydroxybenzoyl)amino]phenyl}piperazine-1-carboxylate

Participants

Reaction Steps

To a 100 mL round bottomed flask with a stirring bar and an argon inlet was added 4-(4-(1,1-dimethylethoxycarbonyl)piperazin-1-yl)aniline (0.868 g, 3.13 mmol), 4-hydroxybenzoic acid (0.525 g, 3.80 mmol), chloro-N,N,N',N',-bis(pentamethylene)formamidinium hexafluorophosphate (1.35 g, 3.74 mmol), and CH2Cl2 (45 mL). This mixture was cooled in an ice bath and diisopropylethylamine (0.96 mL, 5.52 mmol) was added. The ice bath was allowed to expire and the mixture was stirred at ambient temperature 18 h. The mixture was diluted with EtOAc and washed with 10% aqueous citric acid, water and brine. Drying (MgSO4), filtration and removal of the solvent in vacuo gave an oil. This material was chromatographed on 100 g of silica gel using 70% EtOAc-hexane as eluant to give 0.57 g of N-(4-(4-(1,1-dimethylethoxycarbonyl)piperazin-1-yl)phenyl)-4-hydroxybenzamide as a grey solid.

Provenance & Evidence