Hydrochloric Acid → 4,5-Dimethoxy-2-benzofuran-1(3H)-one

Participants

Reaction Steps

3,4-dimethoxybenzoic-acid (5.0 g, 27 mmol) was added to Formalin (36 ml) saturated with hydrogen chloride gas, and stirred with bubbling hydrogen chloride gas at 65° C. for 2 hrs. The reaction solution was concentrated under reduced pressure, and to the residue was added water (16 ml), followed by neutralizing with dilute aqueous ammonia (concentrated aqueous ammonia:water=2:3). The precipitated crystals were collected by filtration, washed with water, followed by drying to give 4.0 g of 4,5-dimethoxyphthalide.

Provenance & Evidence