反应详情

温度

102.5 °C

A suspension of 5 (16.52 g, 72.4 mmol) in neat P(O)Cl3 (21.5 mL, 0.231 mol) was stirred at 100-105° C. for 4 h. The mixture was then cooled to rt., diluted with p-xylene (100 mL) and concentrated to dryness in vacuum. The residue was separated between saturated aqueous NaHCO3— AcOEt. 10% aqueous solution of Na2CO3 was added to basify the aqueous layer to pH 9. Organic phase was separated and the aqueous layer was extracted with AcOEt (8×300 mL). Combined organic solutions were dried MgSO4, concentrated, and the residue was purified by silicagel chromatography (SGC) using CH2Cl2:AcOEt as eluent in gradient to afford recovered starting material 5 (0.76 g, 5%). The desired product was then crystallized from acetone to afford 6 (10.06 g, 56%), thin tan needles. 1H NMR (400 M CDCl3) δ 6.47 (s, 1H), 7.08 (tdd, J=8.1, 2.3, 1.5 Hz, 1H), 7.33 (ddd, J=9.9, 2.3, 1.6 Hz, 1H), 7.38-7.48 (m, 2H), 8.03 (d, J=2.1 Hz, 1H), 8.53 (d, J=2.1 Hz, 1H), 11.46 (bs, 1H).

1. temperatureThe mixture was then cooled to rt
2. concentrationconcentrated to dryness in vacuum
3. customThe residue was separated between saturated aqueous NaHCO3— AcOEt
4. addition10% aqueous solution of Na2CO3 was added
5. customOrganic phase was separated
6. extractionthe aqueous layer was extracted with AcOEt (8×300 mL)
7. concentrationconcentrated
8. customthe residue was purified by silicagel chromatography (SGC)
9. customAcOEt as eluent in gradient to afford
10. customrecovered
11. customThe desired product was then crystallized from acetone