反应详情

Phosphorous oxychloride (7.6 mL, 83.0 mmol) was added dropwise to DMF (150 mL) at 0° C. A solution of 5 (4.5 g, 24.4 mmol) in DMF (30 mL) was added after 15 min. and the reaction mixture was allowed to warm to room temperature for 2 h. The mixture was poured on ice-water (300 g), made alkaline (pH 7-8) with 2 N aq. NaOH, extracted with EtOAc, the extracts were washed with brine, dried (MgSO4), and concentrated. The crude product was purified by flash chromatography on silica gel using 10% MeOH/CHCl3 as eluent. Recrystallization by dissolving yellow solid in hot MeOH and pouring onto cold water afforded 1 (3.9 g, 75% yield) as a white solid. Mp 242-243° C. 1H NMR (300 MHz, MeOH-d4): δ 9.95 (s, 1H), 8.48 (bs, 1H), 8.22 (s, 1H), 7.63 (d, 8.5 Hz, 1H), 7.53 (dd, 8.5, 1.7 Hz, 1H). MS m/z: 212 (M−1). Analysis calcd. for C10H6NOF3; C, 56.35; H, 2.84, N, 6.57; found, C, 56.60; H, 2.92; N, 6.55.

1. additionThe mixture was poured on ice-water (300 g)
2. extractionextracted with EtOAc
3. washthe extracts were washed with brine
4. dry with materialdried (MgSO4)
5. concentrationconcentrated
6. customThe crude product was purified by flash chromatography on silica gel using 10% MeOH/CHCl3 as eluent
7. customRecrystallization
8. dissolutionby dissolving yellow solid in hot MeOH
9. additionpouring onto cold water