反应详情

2-Ethyl-N-(3-fluoro-4-piperazin-1-yl-phenyl)-butyramide. To a solution of 4-(4-amino-2-fluoro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (2.0 g, 8.9 mmol) and Et3N (1.4 mL, 10.0 mmol) in DCM (60 mL) was added 1-ethylbutyryl chloride (1.4 mL, 10.0 mol). The mixture was stirred for 18 h, quenched with 1 N NaHCO3 (50 mL), and extracted with DCM (3×50 mL). The organic layers were combined, dried (Na2SO4), and concentrated. Chromatography of the residue (SiO2; EtOAc/hexanes) gave 4-[4-(2-ethyl-butyrylamino)-2-fluoro-phenyl]-piperazine-1-carboxylic acid tert-butyl ester. A mixture of this intermediate in MeOH (25 mL) and 2 N HCl in Et2O (10 mL) was stirred for 18 h. The solution was concentrated to give 2-ethyl-N-(3-fluoro-4-piperazin-1-yl-phenyl)-butyramide hydrochloride. This salt was treated with 1 N NaOH (10 mL) and extracted with EtOAc (40 mL). The organic layer was dried and concentrated to give the title compound as the free base (1.5 g, 58%). MS (ESI): mass calcd. for C16H24FN3O, 293.19. m/z found, 294.4 [M+H]+. 1H NMR (CDCl3): 7.25-7.23 (m, 1H), 7.17 (s, 1H), 6.58-6.55 (m, 1H), 3.08-3.00 (m, 8H), 2.02-1.99 (m, 1H), 1.80-1.50 (m, 4H), 1.00-0.95 (m, 6H).

1. customquenched with 1 N NaHCO3 (50 mL)
2. extractionextracted with DCM (3×50 mL)
3. dry with materialdried (Na2SO4)
4. concentrationconcentrated