p-Toluenesulfonic acid → 8-((5-((4S,6S)-2-amino-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-4-yl)-6-fluoropyridin-3-yl)amino)-5-fluoro-1,7-naphthyridine-3-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a solution of (4S,6S)-4-(5-amino-2-fluoropyridin-3-yl)-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-amine (6a, 0.076 g, 0.260 mmol) and 8-chloro-5-fluoro-1,7-naphthyridine-3-carbonitrile (intermediate 17, 0.065 g, 0.312 mmol) in 2-propanol (2.6 ml) was added 4-methylbenzene sulfonic acid (monohydrate, Fluka, 0.099 g, 0.520 mmol). The reaction mixture was heated to 100° C. for 1.5 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was partitioned between DCM and aqueous saturated sodium bicarbonate. The aqueous layer was backextracted with DCM. The combined organic extracts were washed with brine and dried over sodium sulfate. The filtrate was concentrated and the residue was purified by reversed-phase preparative HPLC using a Phenomenex Gemini column, 10 micron, C18, 110 Å, 100×50 mm, 0.1% TFA in CH3CN/H2O, gradient 10% to 100% over 20 min. The product containing fractions were combined and neutralized with aqueous sodium bicarbonate solution. The free-based product was extracted with DCM. The organic phase was dried over MgSO4 and the solvent was removed under reduced pressure to afford the title compound (0.054 g, 0.117 mmol, 44.8% yield) as yellow solid. MS m/z=464.0 [M+H]+. Calculated for C20H14F5N7O: 463.4

Provenance & Evidence