反应详情

温度

100 °C

To a suspension of tert-butyl 4-aminobenzoate (6.36 g, 32.9 mmol) and 2,6-dichlorobenzothiazole (5 g, 24.5 mmol) in isopropanol (150 mL) was added 4 N HCl solution in 1,4-dioxane (1.5 mL, 6 mmol). The mixture was refluxed at 100° C. for 7 h, and then allowed to cool to room temperature. The resulting precipitate was isolated by filtration to yield the first crop of the title compound as a white solid (3.13 g). The mother liquor was concentrated in vacuo and then stirred in a mixed solvent of TFA (20 mL) and dichloromethane (20 mL) overnight. The solvent was removed in vacuo, the obtained residue triturated with isopropanol/ethyl acetate. The isolated white solid was further stirred in a mixed solvent of isopropanol (12 mL) and ethyl acetate (8 mL) for 0.5 h, then isolated by filtration to yield a second crop of the title compound (3.5 g) (total 6.63 g, 85%). HPLC/MS (Method C): retention time=2.51 min, [M+H]+=305.3.

1. temperatureto cool to room temperature
2. customThe resulting precipitate was isolated by filtration