The follow article was authored by several reseachers, including the man himself, Alexander T. Shulgin.
In the future, it may prove to be adaptable to a better safer method for the oxidative demethylation of eugenol.
A Convenient Synthesis of Quinones from Hydroquinone Dimethyl Ethers. Oxidative Demethylation with Ceric Ammonium NitrateI'eyton Jacob, 111, Patrick S. Callery, Alexander T. Shulgin, and Neal Castagnoli, Jr.*J. Org. Chem., Vol. 41, No. 22, 1976Here are two excerpts from the article:
As a part of our studies on the metabolism and mechanism of action of psychotomimetic l-phenyl-2-aminopropanes, we required a mild method for the oxidative demethylation of p -dimethoxybenzene derivatives. We have found that ceric ammonium nitrate [Ce(NH4)2(NO& CAN] in aqueous acetonitrile will oxidize a variety of hydroquinone dimethyl ethers (a) to the corresponding quinones (b) often in high yield. The reaction can be carried out in the absence of strong acid, and is generally quite fast, requiring only a few minutes reaction time at room temperature. The selectivity and mildness of the reaction is illustrated by the fact that a variety of functional groups are tolerated.
General Procedure for Oxidative Demethylation.
Unless otherwise noted, the dimethoxy compound was dissolved in acetonitrile, and an aqueous solution of ceric ammonium nitrate (2-3 equiv CeIV) was added portionwise over 5 min. In most cases a transient blue-black color was observed. After stirring for 30 min at room temperature, the reaction mixture was extracted with chloroform. The chloroform extract was concentrated on a rotary evaporator and the crude product was purified by sublimation or recrystallization.
Here are two of the experimental examples printed in the article:
p-Benzoquinone (lb).
To a solution of p-dimethoxybenzene (la, 1.38 g, 10 mmol) in acetonitrile (25 ml) was added a solution of CAN (16.5 g, 30 mmol) in H20 (25 ml). The mixture was extracted with chloroform, the extract was concentrated under reduced pressure, and the residue was sublimed (160 "C, 20 mm) to give the yellow quinone lb (0.61 g, 5.7 mmol, 57%), mp 111.5-112.5 "C (lit.lo mp 114.5 "C).
2,5-Dimethyl-1,4-benzoquinone (2b).
The dimethyl ether 2all (1.0 g, 6.0 mmol) in acetonitrile was treated with aqueous CAN (8.8 g, 16 mmol) to yield the bright yellow quinone 2b which after sublimation (145 "C, 4 mm) gave 0.78 g (5.70 mmol, 95%) of pure product, mp 122.5-123.5 "C (lit.12 mp 123.5-125 "C).