反应详情

A suspension of 6.2 g (0.028 mole) of 1-hydroxy-7-methoxy-2-naphthalenecarboxylic acid in 75 ml of methanol under a nitrogen atmosphere was treated over 15 minutes with 15.0 ml (17.3 g; 0.12 mole) of boron trifluoride etherate. The mixture was stirred at reflux for 45 hours, cooled, and added slowly to 500 ml of ice cold 5% aqueous sodium bicarbonate solution. The precipitated product was filtered, and washed with water to yield 6.0 g (92% yield) of the ester, mp 80°-83°, suitable for further synthetic use. A sample purified by chromatography (silica gel, dichloromethane elution) was analytically pure, mp 79°-81° (a mp of 81°-82° is given by M. E. Alonso, A. W. Chitty, S. Pekerar, and M. de L. Borgo, J. Chem. Soc. Chem. Comm., 1542 (1984).

1. temperatureat reflux for 45 hours
2. temperaturecooled
3. filtrationThe precipitated product was filtered
4. washwashed with water