Triphenylphosphine → tert-butyl 4-(2-(6-((3-ethyl-4-(imidazo[1,2-a]pyridine-3-carboxamido)-1H-indazol-1-yl)methyl)pyridin-2-yloxy)ethyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a suspension of N-(3-ethyl-1-((6-hydroxypyridin-2-yl)methyl)-1H-indazol-4-yl)imidazo[1,2-a]pyridine-3-carboxamide (26 mg, 0.0630 mmol; prepared as in Example 17, Step A) in THF (5 mL) was added tert-butyl 4-(2-hydroxyethyl)piperazine-1-carboxylate (43.6 mg, 0.189 mmol), triphenylphosphine (41.3 mg, 0.158 mmol) and diethyl azodicarboxylate (62.0 μL, 0.158 mmol). The suspension became a clear solution and was stirred for 16 hours. The reaction mixture was concentrated under reduced pressure and the residue was purified by silica gel chromatography (DCM/MeOH 10:1) to provide the intermediate tert-butyl 4-(2-(6-((3-ethyl-4-(imidazo[1,2-a]pyridine-3-carboxamido)-1H-indazol-1-yl)methyl)pyridin-2-yloxy)ethyl)piperazine-1-carboxylate mixed with triphenyl phosphine oxide, to which was added DCM/TFA (2 mL/1 mL). The reaction mixture was stirred for 30 minutes and then concentrated under reduced pressure. Silica gel chromatography (DCM/MeOH/NH4OH 10:1:0.1) provided the desired product (10 mg). MS (ES+APCI) m/z=525 (M+H).

Provenance & Evidence