反应详情

To a mixture of 4-(2,4-dihydroxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester (1.0 g, 4.20 mmol) in dichloromethane (50 mL) was added 3,4-dihydro-2H-pyran (0.38 mL, 8.40 mmol) and pyridium p-toluenesulfonic acid (0.010 g) at room temperature. The resulting mixture was stirred at room temperature for 16 hours then concentrated in vacuo. The residue was purified by silica gel flash column chromatography to give 4-[2-hydroxy-4-(tetrahydro-pyran-2-yloxy)-phenyl]-4-oxo-butyric acid methyl ester (1.1 g, 81%). 1HNMR (400 MHz, CDCl3): 12.40 (s, 1H), 6.95 (s, 1H), 6.90 (s, 1H), 5.90 (br s, 1H), 3.27 (t, J=7.8 Hz, 2H), 2.78 (t, J=7.8 Hz, 2H), 2.30 (s, 3H).

1. concentrationthen concentrated in vacuo
2. customThe residue was purified by silica gel flash column chromatography