Tert-butyl 4-(2-hydroxyethyl)piperazine-1-carboxylate → tert-Butyl 4-(2-(3-(3-methyl-1-((6-methylpyridin-2-yl)methyl)-1H-indazol-4-ylcarbamoyl)imidazo[1,2-a]pyridin-7-yloxy)ethyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a 0.4 M solution of potassium tert-butoxide (0.068 g, 0.606 mmol) in THF cooled in an ice-water bath was added tert-butyl 4-(2-hydroxyethyl)piperazine-1-carboxylate 0.278 g, 1.21 mmol). The reaction was stirred for 10 minutes before adding 7-fluoro-N-(3-methyl-1-((6-methylpyridin-2-yl)methyl)-1H-indazol-4-yl)imidazo[1,2-a]pyridine-3-carboxamide (Example 53; 0.100 g 0.241 mmol) in 2 mL of NMP. The reaction was warmed to ambient temperature and stirred for 1 hour, then heated to 60° C. and stirred for 12 hours. THF was removed by rotary evaporation and the mixture was heated to 120° C. for 5 hours. Another equivalent of potassium t-butoxide was added and the mixture was heated for another 3 hours. The reaction was quenched with water and extracted with EtOAc. The extracts were dried over sodium sulfate and concentrated under reduced pressure. Purification by preparative thin layer chromatography and reverse phase chromatography gave the title compound. MS (APCI), positive scan, m/z=625.0 (M+H).

Provenance & Evidence