Acetic Acid → Methyl 5-hydroxynaphthalene-2-carboxylate

Participants

Reaction Steps

5-Methoxy-2-naphthoic acid (49.7 g, 0.246 mol, J. Med. Chem. 1993, 36, 2485) in glacial acetic acid (450 ml) and in 48% strength aqueous hydrobromic acid solution (450 ml) is heated to reflux for 15 h. After cooling, the reaction mixture is concentrated in vacuo and is extracted with dichloromethiane after addition to water. The orgoanic phase is washed with water, dried over MgSO4 and concentrated in vacuo. The residue is dissolved in MeOH (1.6 1). The solution is saturated with hydrogen chloride (about 1 h), the reaction mixture heating to reflux temperature. The solvent is then stripped off in vacuo, the residue is taken up in ethyl acetate, and the mixture is washed with satd NaCl solution, dried (MgSO4) and concentrated in vacuo. The residue is chromatographed on silica gel using dichloromethane:ethyl acetate (20:1). The product thus obtained is stirred with dichloromethane/petroleum ether, filtered off with suction and dried in vacuo.

Provenance & Evidence