In a 3L flatbottom flask, fitted with a condensor and magnetic stirring, was added 600 ml dichloromethane and 56 g sodium bicarbonate followed by 180 g (1.11 mol) isosafrole. A solution of performic acid, prepared from 120 ml 50% hydrogen peroxide and 230 ml 85% formic acid, was added dropwise over the course of 3 hours, and the mixture was allowed to stir for an additional 22 hours. The organic layer was separated and washed with 3x 200 ml distilled water. After evaporation of the solvent there was left 255 g of a dark red oil, which was stored in the refridgerator for 12 hours, after which it took on the viscosity of motor oil.
The dark red glycol was dissolved in 250 ml methanol in a 3L flatbottom flask fitted with condensor and magnetic stirring, 400 ml distilled water were added and the mixture was heated to reflux with stirring. 430 ml 30% HCl was added and refluxing was continued for 3 hours and the contents were allowed to cool to room temperature. The bottom dark oily layer was separated off (honey-mint smell) and the aqueous layer was extracted twice with 200 ml DCM. The oil and extracts were pooled and washed twice with 200 ml distilled water, once with 300 ml 10% NaHCO3, and once with 300 ml brine. The bicarbonate washing took on a brown color, the other washings were clear. The solvent was stripped off and the residue was distilled with aspirator vacuum: first came a small forerun (15 ml) of isosafrole, followed by 133 gr rose/golden 3,4-methylenedioxyphenylacetone, an overall yield of 67%.
MDP2P was tested positive with bisulfite.
The remainder left in the distilling flask was 25-28ml tar, which had some transparency to it. Aside from the extra yield, this hydrolysis also seems much cleaner, in appearance and work up.
Previous yields using H2SO4 hydrolysis were around 50%.
Well done Chromic.
