Hydrochloric Acid → 5-amino-2-(4-amino-3-fluorophenyl)-6,8-difluoro-7-methyl-4H-1-benzopyran-4-one

Participants

Reaction Steps

50 mL of 1,4-dioxane and 25 mL of concentrated hydrochloric acid were added to 800 mg (1.64 mmol) of the above 6,8-difluoro-2-(3-fluoro-4-pivaloylaminophenyl)-7-methyl-5-pivaloylamino-4H-1-benzopyran-4-one and the mixture was stirred under heating at reflux for 2 hours. The reaction solution was poured into ice water, and the solution was made basic and extracted once with chloroform. The organic layer was washed once with an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (chloroform:methanol=40:1) and recrystallized from ethyl acetate/n-hexane to give 183 mg of Compound 80 (yield: 35%).

Provenance & Evidence