Chromic's buffered peracetic oxidation should yield asarone epoxide. Here are two epoxide -> ketone tales:
It seems like the distillation of asarone glycol (and possibly also the distillaion of the epoxide, if water is present) forms a crystalline by-product,
which is a glycol dimer, and not solely 2,4,5-trimethoxyphenyl-2-propanone.
Asarone 1,2-glycol
Distillation of asarone 1,2-glycol (an oil) at 170-230°C/4 mmHg gives a red oil, which solidifies on standing. Through crushing the crystals under ether, a solid was left undissolved, which after recrystallization from alcohol melted at at 204-205°C, and had the molecular formula C24H32O8 [Could possibly be the 2,5-dimethyl-3,6-(2,4,5-trimethoxyphenyl)-1,4-dioxane cyclic ether]. Evaporation of the ether from which the dimer was separated gave an oil which partly crystallized, and after purification through its semicarbazone (mp 157-158°C), 2,4,5-trimethoxyphenyl-2-propanone (mp 47-48°C) was obtained. On heating asarone 1,2-glycol with acetic anhydride, the dimeric compound is formed in quantitative yield.
Reference: J. Chem. Soc. 1338 (1937)
Here is an anonymous contribution too:
Laugh at SWIM's yield, go ahead. But should she embark on a more sensible quarter-mole run, starting with 52 g asarone, in sizes where she can see what's going on, she'll expect me to put that in Novel discourse, when it's done. (I'll try to keep it down to novella length, though.) smile The point I wanted to establish in this post, is that thermal rearrangement of the epoxide works with asarone.
Using: Chromic's 100 mmole scale verbatim with 20.8 g asarone, 72.7 g oxone buffered with 24.4 g Na bicarbonate, in 500 ml water/200 ml methanol. The solution turned red about an hour into the reflux. For the workup, SWIM added 20 g Na bicarb, bringing the pH up to 8 before she distilled off the methanol. During the distillation, the flask contents were strongly black-red. She filtered with aspirator suction. With the methanol and solids out, she botched the extraction. With DCM, she was still pulling color on the sixth 40-ml separation, but discarded the solution. Undoubtedly she tossed some of her epoxide there. She may go back to ether extraction, more used to it.
With the DCM distilled under ambient pressure, she refluxed the epoxide 1 hour, with no companionship in the flask except the stir bar. She then rigged a short-path setup by attaching her thermometer adapter directly to the vacuum adapter (hose fitting plugged with a twist of tissue paper), like a straight distillation setup minus the condenser. When the distillation got busy, with a lot of drops of throughput, damp tissue laid over the adapters gave cooling. She got only 11.3 g crystal clear ketone, a 50% yield from asarone. Tale of woe: the heating mantle there is dead. She can see 10 ml undistilled limpid black oil left. To get it at ambient pressure, though, she'll have to go to the camp stove with open flame. Her hotplate/stirrer with mineral oil bath is left behind in the dust, just won't cut it. She even used foil, still not enough heat.
So there's no doubt at all, you can get over 50% crystal clear ketone from asarone, better than her. She aminated by Sonson's (MDP2P) hydroxylamine route to the oxime, using 10.8 g Na acetate and 5 g hydroxylamine HCl, in 10 ml water/40 ml MeOH. For the reduction of the oxime, she dissolved it in 100 ml denatured alcohol and 40 ml water, and added 7.0 g potassium hydroxide. The "unactivated" stage Urushibara nickel catalyst, 10% Ni deposited on 40-60 mesh aluminum granules, was then added, 2 grams of it, to this basic solution. Hydrogen generation was extended on 3 occasions by addition of 0.5 g aluminum flake, 50-80 mesh, at about 90 minute intervals. She used a microwave heating technique, a 30 second cycle whenever the tiny H2 bubbles slowed, or after adding more aluminum. Finally, though, she set the flask on the stirrer. Never mind the etching effect on glassware, of tiny nickel granules. For the last hour, she stirred @ 40°-50°. (If warmed and stirred the whole time, the reduction would bee complete in 4 hours. No help from microwaves in this case, but cheap entertainment to watch.)
The TMA-2*HCl is the real McCoy, bioassay by my buddy SWIM shows. (She took a preview taste test.) Got 9.3 g wet weight.
