反应详情

49.5 g of 2-(3,4-dimethoxy-α-hydroxybenzyl)-3,4,5-trimethoxybenzaldehyde dimethyl acetal are dissolved in 5 ml of toluene. 14.2 g of dimethyl acetylenedicarboxylate and 19 mg of p-toluenesulfonic acid monohydrate are added to the solution, and the mixture is refluxed for 3 hours. After cooling the reaction mixture, 200 ml of methanol are added thereto, and the mixture is allowed to stand at -30° C. overnight. The precipitated crystals are collected by filtration and recrystallized from ethyl acetate to give 33.1 g of 1-(3,4-dimethoxyphenyl)-2,3-bis(methoxycarbonyl)-4-hydroxy-6,7,8-trimethoxynaphthalene as colorless prisms.

1. temperaturethe mixture is refluxed for 3 hours
2. additionare added
3. filtrationThe precipitated crystals are collected by filtration
4. customrecrystallized from ethyl acetate