peracetic oxidation of asarone to ketone

[boppesz]

YES!!!!! Electronic oxidation. Should we start a new forum for this? I think this must be the best way the make the lovely ketones, but there isn't much info on this subject. Is there anyone with experiences with this?

[Antibody2]

i also would like to hear more on the electrochemical route, please elaborate synthomatic.

btw- RC also reported success with the O2 wacker
and i think Dr_Sister also reported a minor sucess with the benzowacker, but there was lots of byproduct if i recall.
"All those memories lost like rain..."

[foxy2]

The electrochemical wacker is on a primary olefin, I doubt it will work on asarone.

I have other refs about PTC mediated wackers(details later) and they only worked for terminal olefins and the electrowack on rhodiums site seems to bee a PTC rxn.
Do Your Part To Win The War

[Chromic]

I was thinking more of the buffered Oxone technique... it is the European root that is desired, correct? I'd love to get it a swing, although it is an expensive oil... I suppose the Leukart would be nice to learn tho.

[moo]

If I recall correctly, they all contain minor amounts of gamma-asarone (the allylbenzene) and the others (alpha and beta) are cis and trans isomers of the propenylbenzene, so it really shouldn't matter. Although I cannot remember which was cis and which was trans, it can be found out using Google.
^{understanding is everything}

[Osmium]

You want the asian/indian/nepalese/whatever oil, that's the 80% stuff.

[Dr_Sister]

chromic - the european variety is the one you don't want.
7.10.01

[uemura]

sYnThOmAtIc,
you said for electrochemical oxidation:
It is a very high yielding method for sure on the isoeugenl and isosafrole the only ones tested by my monkey (89&93%). Any references? Could your monkey make a nice writeup? Everything appreciated Carpe Diem

[boppesz]

I think the ref synthomatic read is the following:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/guest.eugenol.txt

Very very interesting. I'm doing research now on this subject, and after I prepared an electrolytic cell, I will experience, and share my results with yo guys. But this may take a few months.  Another thing: I read somewhere (no refs) that wacker only works on none-substituted propenylbenzenes, so no safrole etc. etc. So skip the wacker and do research in electrolytic oxidation.Let's help each other!!!

[Chromic]

I can't wait to give the Oxone reaction on asarone a try. Hopefully I'll have enough time this year to workup the glycol and do an NMR on a sample.

[sYnThOmAtIc]

No problem. I'll rob him of his notes tonight once the evil professor releases him from the clinic to go to the zoo.

It's no bulshit and it does work. He showed my friend his results in an alley around downtown half past midnight. He told me he plans to do an electroreduction with the resulting residue.

I do know his only references were that of electroepoxidation refs on rhodiums page only. Bee back soon wiht his notes.

Personally I think this is by far the easiest, cheapest, highest yielding procedure which he has showed me.

Plus it is.. COMPLETELY OTC.

Here was the procedure he recreated.

6.5g NaBr from brominating tablets was added to a beaker containing 25ml distilled water. Magnetic stirring is commenced and a mixture of 125ml methyl cyanide and 4.38g isosafrole is added to the beaker and the resulting mixture is mixed for several minutes and a styrofoam faucet cover is placed around beaker to keep a constant temperature. Two small graphite slabs are lowered into solution separated by a stainless steel blade and a current of 1ampre is passed through electrodes for 109 minutes. As the document calls for 2-2.6 faradays per olefin mole and this contains .0263 moles 6597.66 coulombs are passed at 1amp in 109 minutes or at five amps can be completed in 21 minutes. Magnetic stirring is stopped and allowed to settle a minute and 250ml of 20% NaCl solution is added and epoxide is extracted with ethyl acetate preferably or toluene/dcm and is washed 2x/w n20%NaCl solution. Then the obtained epoxide in solution was refluxed directly in ethyl acetate after drying with epsoms with 700mg of LiI obtained from photography batteries. If ethyl acetate is not avail then hydrolysis with h2so4 is possible by the very familiar procedure to most I'm sure. The final yield was 4.33g piperonylacetone.

More elaboration can be provided on various things and yields if anybody whishes to dream about recreating or tweaking this method for isosafrole and other similar compounds.

[Antibody2]

1) how well does that scale?

2) could you elaborate on the stainless steel plate, size of vessel etc. pls.

3) where is methyl cyanide otc?

thanx
"All those memories lost like rain..."

[Rhodium]

Methyl Cyanide (acetonitrile, CH3CN) is not OTC anywhere I know of.

[foxy2]

I have not seen it in person, however on the web it is listed as a fingernail polish remover.  There are reports of deaths due to drinking ACN fingernail polish remover.

google
Do Your Part To Win The War

[terbium]

solution separated by a stainless steel blade
This part I don't understand. What is the purpose of the "stainless steel blade"?

[boppesz]

The reaction also can be done in DMF or DMSO

[sYnThOmAtIc]

No methyl cyanide is not otc but other dipolar aprotic solvents are, MEK, acetone, THF, ether, DCM, DMSO, DMF, and formamide the latter three can be synthed pretty easily.  Plus others, dunno just look up solvents that lack an OH grouping. 

Pinky tried using MEK alst night as direct replacement after distilation and got 4.35g. As soon as I track down pinky and my calipers I will give the exact dimensions of anodes and cathode. The cathode was just a blade from a stainless butter knife that had been hacked off to use in the experiment. Correction on the 93% it is 89.9% from iso to acetone with methyl cyanide.

But this one yielded 90.4% from the same 4.38g ammont with MEK.

[sYnThOmAtIc]

Terbium: SS balde is the cathode with two graphite anodes on either side of the blade.

The electricity discharging into the solution oxidizes the compound at the anode and the cathode reduces but the epoxide can't be reduced until further workup so there is no need for a partition in the cell as would be if this were a reduction reaction which the product of this goes next.

[uemura]

Bees,
This gives a bit more details. It is extracted from Rhodium site, see

https://www.thevespiary.org/rhodium/Rhodium/chemistry/guest.phenylacetone.txt

for a full description.

Therefore, the object of the present invention is a process for preparing 3,4-dimethoxyphenylacetone, characterised in that:
(a) isoeugenol-methylether, having the formula: 3,4-(MeO)2.C6H3.CH=CH.Me is submitted to an electrolysis in a not-partitioned electrochemical cell, in a medium comprising a dipolar aprotic solvent and an aqueous solution containing an alkali metal bromide or an alkali-earth metal bromide or a quaternary ammonium bromide, in such an amount as to have at least 0.6 mol of Br- ions per water litre, with graphite anodes or anodes constituted by titanium, coated with oxides of precious metals of the VIII group or with mixed oxides thereof with valve metals selected from Ti, Nb, Ta and Zr, and that:

(b) the epoxide isolated from the reaction mixture resulting from (a) step is submitted to an isomerization, in an inert organic solvent and in the presence of catalytic amounts of a lithium salt selected from lithium iodide, bromide and perchlorate, by being heated at temperatures comprised within the range of from 50° C to the solvent refluxing temperature, to produce a methyl ketone III. The electrolysis reaction (a), leading to the formation of the epoxide, can be carried out both batch-wise and continuously, at temperatures comprised within the range of from 0° C to 50° C, preferably of from 10° C to 30° C, with current intensities higher than 100 A/m2 being used, and with the reaction mixture being kept stirred, by a stirring of mechanical type, or obtained by exploiting the turbulence as generated by the gases formed during the electrochemical reaction.

As the dipolar aprotic solvents, e.g., acetonitrile, dimethylformamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone and dimethylacetamide, preferably acetonitrile and dimethylformamide, can be used.