反应详情

Trifluoroacetic anhydride (1.27 g, 840 μL, 6.04 mmol) was added under ice cooling to a solution of 2-chloro-3-(1-fluorocyclobutyl)-6-methylpyridine 1-oxide (Example 130 c, 869 mg, 4.03 mmol) in dichloromethane (10.9 mL). The mixture was stirred at ambient temperature for 72 h. Upon ice bath cooling 5 N NaOH solution (1 mL) and afterwards ice water (20 mL) were added. The mixture was extracted with dichloromethane (2×40 mL). The combined organic layers were washed with icewater/brine (20 mL), dried over Na2SO4 and concentrated in vacuo. The residue was purified by flash chromatography (silica gel, 50 g, heptane/EtOAc 0-40% in 120 min.) to give the title compound (279 mg, 32%) as light yellow oil, MS (ESI): m/e=216.3 [MH+].

1. additionwere added
2. extractionThe mixture was extracted with dichloromethane (2×40 mL)
3. washThe combined organic layers were washed with icewater/brine (20 mL)
4. dry with materialdried over Na2SO4
5. concentrationconcentrated in vacuo
6. customThe residue was purified by flash chromatography (silica gel, 50 g, heptane/EtOAc 0-40% in 120 min.)