3-((4-(4-Amino-2,5-difluorobenzoyl)piperazin-1-yl)methyl)-N-tert-butylbenzamide (1 g, 0.023 mol) and 4-nitrophenol chloroformate (0.4636 g, 0.0023 mol) were combined and stirred in dichloromethane for 1 hour at room temperature. Cyclobutylamine (0.8969 g, 0.0017 mol, 0.108 mL) was added and the reaction was stirred for 30 minutes. The reaction mixture was diluted with water and flushed through a hydrophobic frit. The organic phase was concentrated under vacuum and purified by acidic reverse phase HPLC to afford the title compound (21 mg).
