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

Participants

Reaction Steps

Under mechanical stirring a slurry of 3,4-dimethoxybenzoic acid (353.5 g, 1.94 moles) in HCHO (1.71, 24.5 moles) was prepared and cooled in ice, saturated with gaseous HCl (340 g, 9.32 moles), then gradually brought to 60° C. After 1 night the temperature was brought to room value and further HCl (300 g) was gurgled therein, then the temperature was brought to 60° C. again overnight. The mixture was brought to small volume, taken up in water (1 l), neutralized with 28% NH4OH (1.5 l) and kept at cold for 2 hours, then filtered. The filtrate was washed with water till neutrality, then crystallized from methanol (2 l) and dried under vacuum at 60° C. to give 220 g of the title product (yield: 58.65%).

Provenance & Evidence