Hydrochloric Acid → 5,6-Dimethoxy-3H-isobenzofuran-1-one

Participants

Reaction Conditions

Reaction Steps

A suspension of 3,4-dimethoxy-benzoic acid (353.5 g, 1.94 moles) in HCHO (1.7 l, 24.5 moles) under stirring was prepared and cooled in ice, saturated with gaseous HCl (340 g, 9.32 moles), then gradually warmed to 60° C. After one night the temperature was cooled to the room value and further HCl (300 g) was bubbled in, then the temperature was brought again to 60° C. for one night. The mixture was partially evaporated, taken up in water (1 l), neutralised with 28% NH4OH (1.5 l) and kept at cold for 2 hours, then filtered. The filtrate was washed with water up to neutrality, then crystallised from methanol (2 l) and dried under vacuum at 60° C. to give 220 g of the title compound (yield: 58.65%).

Provenance & Evidence