A mixture of isobutyl 3-(5-((1R,2S)-2-amino-1-(4H-benzo[d][1,3]dioxin-7-yl)propoxy)-1H-indazol-1-yl)benzoate (420 mg, 0.84 mmol) (I5b), 2,2-difluoropropanoic acid (213 mg, 1.94 mmol) and HBTU (420 mg, 1.11 mmol) were suspended in dichloromethane (10 mL). N-ethyl-N-isopropylpropan-2-amine (0.85 mL, 5.13 mmol) was added and the mixture was stirred at room temperature overnight. Water (ca 10 mL) was added to the solution. After stirring for some minutes the mixture was added to a phase separator. The water phase was stirred with dichloromethane (5 mL) and added to the phase separator. The combined organic phases were concentrated to a brown oil. Purification by flash chromatography on silica (dichloromethane/ethyl acetate 10/1) gave the title compound as a white foam (400 mg, 80%).
