tert-Butyl methyl ether → tert-Butyl 4-((6-(5-(2,6-difluorophenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yl)(methyl)amino)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a glass microwave vial was added 3-(6-chloropyrazin-2-yl)-5-(2,6-difluorophenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole (0.200 g, 0.469 mmol), dicyclohexyl(2′,6′-diisopropoxybiphenyl-2-yl)phosphine (RuPhos, 6.57 mg, 0.014 mmol), chloro(2-dicyclohexylphosphino-2′,6′-dipropoxy-1,1′-biphenyl)[2-(2-aminoethylphenyl)]palladium(II), methyl-t-butylether adduct (6.57 mg, 0.014 mmol), RuPhos precatalyst (10.28 mg, 0.014 mmol), and sodium tert-butoxide (0.144 mL, 1.174 mmol). The vial was placed under vacuum and flushed with argon. tert-Butyl 4-(methylamino)piperidine-1-carboxylate (0.121 g, 0.563 mmol, CNH Technologies) and THF (1.565 mL) were added and the reaction mixture was stirred at 85° C. overnight. Reaction was cooled to RT. The crude product was adsorbed onto a plug of silica gel and chromatographed through a Biotage pre-packed silica gel column (40S), eluting with a gradient of 10% to 100% EtOAc in hexane. The desired tert-Butyl 4-((6-(5-(2,6-difluorophenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yl)(methyl)amino)piperidine-1-carboxylate was obtained and then treated with 5-6 M HCl in IPA. The reaction mixture was heated at 80° C. for 1 h and then contracted to dryness. The crude product was purified by reverse-phase preparative HPLC using a Phenomenex Synergi column, 4 micron, MAX-RP, 80 Å, 150×30 MM, 0.1% TFA in ACN/H2O, gradient 15% to 100% over 15 min. The title compound was obtained. MS (ESI, pos. ion) m/z: 421.1 (M+1).

Provenance & Evidence