To a solution of 3-tert-butyl-1-p-tolyl-1H-pyrazol-5-amine (5) (447 mg, 1.75 mmol) in DCM (40 mL) was added saturated aq NaHCO3 solution (27 mL). The mixture was stirred vigorously and was cooled to 0° C. and then trichloromethylchloroformate (0.63 mL, 5.25 mmol) was added in one portion. The resulting mixture was stirred at 0° C. for 1.5 hr. The biphasic mixture was separated and the organic layer was dried (MgSO4) and evaporated in vacuo. The oily residue which was taken up in THF (15 mL) and was added to a solution of 4-(2-(4-aminonaphthalen-1-yloxy)propan-2-yl)pyridin-2-amine (42) (253 mg, 0.86 mmol) in THF (2.0 mL). Neat DIPEA (451 μL, 2.59 mmol) was added and the reaction mixture was stirred at RT for 2 hr. Water (30 mL) and EtOAc (20 mL) were added and the layers were separated. The aqueous layer was extracted with EtOAc (3×15 mL) and the combined organic layers were washed with brine (40 mL), dried (MgSO4), and evaporated in vacuo. The residue was purified by flash column chromatography (SiO2, 40 g, 0-10% MeOH in DCM, gradient elution) to afford the title compound (Interm. H) (249 mg, 51%) as a purple amorphous solid: m/z 549 (M+H)+ (ES+).
