Ethyl Acetate → 7-Benzyloxy-6-methoxy-4-(3,4,5-trimethoxyphenyl)isocoumarin-3-carboxylic acid

Participants

Reaction Steps

To a solution of 5-benzyloxy-4-methoxy-2-(3,4,5-trimethoxybenzoyl)-benzoic acid (90 g) in dimethylformamide (900 MI) are added potassium carbonate (60.5 g) and di-tert-butyl bromomalonate (64.6 g), and the mixture is stirred at room temperature for three hours. To the reaction mixture are added ethyl acetate and water. The ethyl acetate layer is separated, washed, dried, and concentrated under reduced pressure. To the residue is added a 4M solution of hydrogen chloride in ethyl acetate (500 ml), and the mixture is stirred at room temperature for five hours. The precipitated crystals are collected by filtration, washed, dried, and dissolved in a mixture of acetic acid (40 ml) and dioxane (80 ml). The mixture is heated under reflux for five hours, and the precipitated crystals are collected by filtration. washed, and dried to give 7-benzyloxy-6-methoxy-4-(3,4,5-trimethoxyphenyl)isocoumarin-3-carboxylic acid (70.0 g) as listed in Table 59.

Provenance & Evidence