反应详情

Compound 1A (2.2 g, 7.6 mmol) was treated with a solution of K2CO3 (2.0 g, 14.8 mmol) in water (9 mL) at ambient temperature. Methyl alcohol (70 mL) and acetone (70 mL) were added and the mixture was heated to reflux for 18 hours. The reaction was cooled to ambient temperature and treated with acetic acid (2.0 mL, 35 mmol), and then concentrated to approximately 30 mL. The resulting suspension was cooled to 0° C. and the product was recovered by vacuum filtration to afford 1B (1.1 g, 79%). HPLC tR=0.405 min (YMC S5 Combiscreen ODS 4.6×50 mm, 10-90% aqueous methanol containing 0.2% H3PO4, 4 min gradient, monitored at 254 nm). 1H NMR (400 MHz, DMSO-d6) δ 10.4 (s, 1H), 8.13 (br s, 2H), 7.31 (br s, 1H), 7.10 (br s, 1H), 6.88 (t, 1H, J=2.0 Hz), 6.75 (dd, 1H, J=1.6, 4.0 Hz), 6.05 (t, 1H, J=3.6 Hz).

1. temperaturethe mixture was heated
2. temperatureto reflux for 18 hours
3. concentrationconcentrated to approximately 30 mL
4. temperatureThe resulting suspension was cooled to 0° C.
5. filtrationthe product was recovered by vacuum filtration