N-bromobutanimide → 2-Formyl-4,5-dimethoxybenzoic acid

Beteiligte Stoffe

Reaktionsschritte

A mixture of 5,6-dimethoxy-3H-isobenzofuran-1-one (10 g, 51.5 mmoles), obtained as described in example 1, under N2 in CCl4 (250 ml), N-bromo-succinimide (13.88 g, 77.25 mmoles) and benzoyl peroxide (320 mg, 1.23 mmoles) was kept under reflux for 2 hours, then cooled, filtered and washed with a 10% Na2SO3 solution (200 ml), then with water, anhydrified and brought to dryness. The residue was taken up with 5% HCl (100 ml) and kept under reflux for 4 hours, then the solution was cooled, basified with NaOH, washed with ethyl acetate and slowly re-acidified to give a precipitate which was filtered, washed with water, dried on P2O5 under vacuum to give 6.43 g of the title compound (yield: 60%).

Herkunft & Nachweise