Propiovanillone

synthetischePreparation by Fries rearrangement of 2-methoxyphenyl propionate, (b.p.20 140–143°)with aluminium chloride in nitrobenzene, first at 60–80° for 1 h, then at r.t. overnight, at 60° for 1 h or at 50° for 5 h (44%) ;with aluminium chloride (2 mol) in nitromethane at r.t. for 24 h (65%)with aluminium chloride in carbon disulfidewith titanium tetrachloride (2 mol) in nitromethane at r.t. for 24 h (62%)with stannic chloride (2 mol) in nitromethane at r.t. for 24 h (69%)with antimony pentachloride (2 mol) in nitromethane at r.t. for 24 h (28%) with formation of important tars.