Ketones from Propenylbenzenes via the di-bromides

[uemura]

The following experimental procedures disclose an old, but in the Hive not much -if any- discussed or known approach from the propenylbenzenes to the 2-propanones.

The methods to be shown are easy, do not require any special chemicals and give all high yields in each of the steps from the propenylbenzen to the ketone. Likely not state of the art -the procedures are almost 100 years old-, this write-up gives nevertheless one so-far UNKNOWN clue on the epoxide-ketone re-arrangement mechanism.

The write-up is mainly based on the article of (1) Höring, 'Über die Dibromide aromatischer Propenylverbindungen', Ber 38, 1905, pg. 3464 and the article of (2)  Mannich, 'Studien in der Reihe des Adrenalins', Arch. Phar. Bd 248, 1910, pg. 127. Uemura picked up the essential details from these two papers, some notes are added the end.

It should be noted that the authors have performed the ketone preparation on the anethole and isosafole, but, and this is where it may becomes interesting, it could work for the acid sensitive asarone as well.

Isosafroledibromine  (CH2O2:)C6H3.CHBr.CHBr.CH3
100g Isosafrole is diluted with 100ml petrol ether. Under cooling with ice a solution of 100g bromine in 100ml petrol is added drop wise. If cristals of the Isosafrolebromide are around, some cristals are added to initiate cristallisation when the addition of bromine has finished. The flask is put on ice and the lower part consisting of the dibromide gets solid after some hours.
Yield 203g. The dibromide does not easily cristallize. mp is 52-53DegC. [N1]

Isosafrolebromhydrine (CH2O2:)C6H3.CHOH.CHBr.CH3
100g Isosafroledibromine are dissolved in 300ml acetone, water is added as long as the solution stays clear (appr. 50ml). In addition, 16g of marble pieces (CaCO3) are added to catch up the HBr which is produced by the hydrolyse of the dibromide. Carbon dioxide develops already in the cold. The mixture is heated then 2 hours on a hot waterbath. After 2 hours the aqueous CaBr2 solution is removed and another 40ml water is added. 2 more hours the rxn is heated on a water bath. Then the acetone is removed by destillation. The oily Isosafrolebromhydrine is extracted with ether [N3], the ether solution is washed with water and dried in vacuum. Evap the ether. Yield 98%.
The Isosafrolbromhydrine cannot be destilled in vacuum but will be used as it is for the next step. [N2]

Isosafroleepoxide (CH2O2:)C6H3.CHOCH.CH3
100g Isosafrolbromhydrine are disolved in 100ml alcohol. A solution of 25g KOH in 200ml alcohol is added. Immediately KBr seperates. The alcoholic solution is refluxed on a waterbath to complete the reaction. [N4] Most of the alcohol is then removed by destillion. The solution is poured into water and the Isosafroleepoxide extracted with ether [N3]. Ether solution is dried and evaporated. Yield with respect to the dibromide is 88%.
The Isosafroleepoxide is a colorless, good smelling oil which boils between 143-147DegC under 12mm pressure. [N5]

Piperonyl-acetone (CH2O2:)C6H3.CHOCH.CH3 i.e. Isosafrole-2-propanone
The conversion of the Isosafroleepoxide into the ketone starts when the epoxide is heated to 220 DegC in a flask equipped with a air-cooled condenser. The temperature jumps up quickly to 280DegC. When the exothermic rxn has finished, the mix is refluxed for a short period of time. The first destillation under normal pressure yields a colorless, almost non-smelling oil, which comes over between 280-290DegC. Under 10mm pressure it boils between 149-151 DegC. Yield 80% [N6]

Isosafrole-2-propanone-oxime (CH2O2:)C6H3.CHNOHCH.CH3 [N7]
3g ketone are solved in ethanol, 3g Hydroxylammonumchlorid, solved in a minimum amount of water, are added and the combined solution is make alkaline with concentrated Na2CO3 solution. After standing (hours..) and dilution with water, needles of the oxime seperate. They melt at 87DegC. Recrist. from ethanol or et ether.

Notes:
1: Hörig uses ether instead of pet ether for the bromation. The dibromide is used as it is for the next step.
2: Mannich adds the calcium carbonate during the rxn. For the preparation of the corresponding asarone-bromihydrine the Höring approach with pieces of marble should work better, since the Hbr is removed when it's produced.
3: Any other non-polar solvent should also be fine.
4: No duration specified by Höring.
5: There are of course other methods around to get to the epoxide, e.g. per-acetic methods or oxidation with H2O2 in MeCN/MeOH.
6: The conversion can also be performed by mixing the Isosafroleepoxide with GAA and adding some drops of H2SO4. But the main interesting point is, the epoxide does not explode but re-arranges into the ketone!!!! And: No need for Li-salts and ethyl-acetate for the rearrangment. Just use HEAT The per-acid method will not likely work for asarone.
7: This is more for information. Oximes may however also be reduced to the amine, there are examples on the chief bees site. The anethole-oxime comes in a two isomeric variants with mp 61-62DegC and with a mp of 72-74DegC.
Carpe Diem

[uemura]

Yes,
they had to heat it up to start the epoxide->ketone re-arrangement which anyway heats the whole stuff up even more. Then they destilled it under normal pressure. A vaccuum destillation after the conversion has seized should even get a more clean product.
Again, if just heat allows the rearrangement from epoxide to ketone, this would be optimal for asarone, since acid catalysed rearrangements (e.g. in GAA) may not work in this case. Carpe Diem

[psychokitty]

I could swear that I once read that they used a catalytic amount of sulfuric acid to rearrange the epoxide to the ketone.

[uemura]

The author Hoering was aware of that. He wrote: 'to get the epoxide any traces of acid must be avoided otherwise conversion to the ketone may take place.' His main interest was not an efficient way for ketone production, but to put the emphasis on the 'intramolecular transition of atoms' which seemed to be a hot issue at this time. Carpe Diem

[megamole]

Can't epoxides be rearranged using a lithium catalyst, like LiBr or LiI?

[Rhodium]

That too. Any lewis acid does the job.

[uemura]

Yes, this is the 'standard' way of re-arrangement. Refluxing the epoxide in ethylacetate with LiBr or LiJ. Unfortunately Uemura got two different products when he applied this for the asarone-epoxide he got from the H2O2 epoxidation in MeCN/MeOH. This is why he is still seeking for other routes to the ketone. Carpe Diem

[PrimoPyro]

That too. Any lewis acid does the job.

Rhodium, could you use aluminum chloride (AlCl₃)? And if so, would the hydrated form be suitable? I'm referring to the hydrate produced upon addition of muriatic to Al foil.

                                                  PrimoPyro

I collect synthetic drug precursers. Aren't you jealous? Member: C_F and pyrotek FanClubs  

[Rhodium]

The problem with many of the stronger lewis acids (such as AlCl3) is that they are likely to rupture the methylenedioxy ring. That's why the less strong LiI is preferred for isosafrole epoxide rearrangement.

[Ritter]

Since lithium iodide is a prevalent reagent in this thread, SWIM thought he'd pass on his experience synthesizing it.  The reaction is very elementary, a simple metathesis reaction between lithium chloride and sodium iodide does the trick.  Simply dissolve equimolar portions of LiCl(anhydrous if possible but not necessary) and NaI in separate portions of anhydrous methanol and combine the solutions.  Precipitation starts immediately and chilling the vessel in crushed ice accelerates the displacement.  The ppt can be difficult to isolate through standard vacuum filtration so SWIM has found that doing the rxn. in test tubes then spinning them down in a centrifuge produces nice compact pellets of anhydrous LiI.  This synth was posted on the Hive many years ago and I'm fairly sure it is no longer in the database.  Anhydrous LiI is a DEA watchlist item so you are best off making it yourself.  Lithium chloride is commonly used for making solder fluxes and ordering it attracts no unwanted attention.

[Rhodium]

Great! Have you used the LiI for this expoxide transformation? Yields?

[Osmium]

I thought NaCl was insoluble in MeOH?

[sunlight]

Merck:
Methanol usually is a better solvent than ethanol, dissolves many inorganic salts, e.g., sodium iodide 43%, calcium chloride 22%, ammonium nitrate 14%, copper sulfate 13%, silver nitrate 4%, ammonium chloride 3.2%, sodium chloride 1.4%.

[IudexK2]

So in the recent article posted in the chem forum where they reflux the dibromo-compound with 85% KOH, are they actually refluxing the epoxide to turn it into a p2p?

[Masquerade]

Lithium Hypochlorite and acide hydrochloric give lithium chloride.
Lithium Hypochlorite and acetone/butanone give lithium acetate/propanoate and chloroform.
Lithium Acetate and acide sulphur give lithium hydrogen sulphate.
Useful??

[uemura]

Bees,
now having an easy way to get LiJ, the conversion with Ethylacetate seems to be easy. But Uemura still would like to find out, why the H2O2/MeCN epoxidation followed by conversion with LiBr/EtAc worked fine for anethol but not for asarone.
Any idea? Carpe Diem

[Rhodium]

Which step failed? The epoxidation or the isomerization?

[Ritter]

Osmium,
d'oh, your right, the supernatant contained the lithium iodide.  Its been a long time.

Rhodium,
Have never run the epoxide rearrangement with LiI.

[otto]

Hi uemura,

>Again, if just heat allows the rearrangement from epoxide >to ketone, this would be optimal for asarone, since acid >catalysed rearrangements (e.g. in GAA) may not work in >this case.

in the Houben-Weyl a 80% yield is given for the thermal rearrangement from asarone epoxide to the ketone. dont know the exact volume, page etc. though.

otto

[uemura]

Bingo...
Thousend thankxs Otto!!! Uemura has access to all the 30+ volumes of the Houben-Weyl in his preferred library. If you find the ref. posting will be appreciated. Uemura will translate and post as soon as he found it.

To Rhod: It's not completely clear which step failed. At the time he did the anethol/asarone epoxidation rxn Uemura was reluctant to destill the epoxides because he was not sure how stable the expoxides would be. The anethol run as described by Osmium gave a reasonable bisulfite compound at the last step without purification (i.e. destillation). The asarone-"ketone" gave none! So Uemura vacuum destilled the 8-10ml (say) and got two fractions, a green oil first, which cristallised after some days and a smaller amount of oil, which also cristallised later on in the flask (together with some brown polymerised? stuff). Because of the small yield of material no further investigation have been performed at this time. Carpe Diem

[Osmium]

Are you sure about the asarone epoxide rearrangement being in Houben-Weyl??? I know I saw the isosafrole rearrangement a few years back, but asarone? Very strange, I doubt I would have overlooked that.

> The anethol run as described by Osmium ...

Huh? What did I describe? Wasn't me for sure.

[uemura]

Osmium,
you described it for isosafrole in 'MDP2P from Isosafrole via Epoxide Intermediate' (see

https://www.thevespiary.org/rhodium/Rhodium/chemistry/safrolepoxide.html

) . It worked for anethole as specified.
Where to check in the Houben-Weyl? Uemura has identified the volume which contains 'Preparation and Reactions of Epoxides' (appr. 100pages). Should it be in here or under other volumes dealing with ketones, or oelefins or.... Carpe Diem

[otto]

hi uemura and osmium,

i am not quite shure, i think it was in one of the ketone-volumes. there was a table given w/ various epoxides and refs. it was also stated that there will be a certain amount of the 1-ketone depending on the epoxide.
unfortunately right now otto has no access to the Houben-Weyl.
the 2,3-epoxide will also rearrange to give the 2-ketone. but i doubt that a similar preparation via the dibromide would work. the first bromine in the ISO-dibromo-compounds is benzylic, therefore easily exchanged, in the 2,3-dibromos its not.
otto is questioning, wether a different pathway would be possible. having the halohydrine, one could try to exchange the halogene with ammonia giving a propanolamine. this could be converted into the corresponding amphetamine by oxidation to the aminoketone and its subsequent (Clemmensen-)reduction.

otto

[Rhodium]

I doubt the aminoketone can be reduced in good yields with the clemmensen. The acidic conditions seem to invite the compound to dimerize.

[twodogs]

Uemura...The epoxide to ketone rearrangement by heating was discussed in a thread in Chemistry Discource called "Li catalysed pinacol rearrangement possible?" The reference you are looking for regarding this is Methoden der Organischen Chemie Pg 934 Volume 7,2(a) Ketones. This has a table with a number of epoxide to ketone reactions by simply heating. Reference is also made to  P Hoering - Ber Vol 38 Pg 3477 (1905). He states that both Isosafrole and the Anisyl epoxides produce the ketone when distilled.  10 grms of the isosafrole epoxide heated to 220C -280C distills over giving 8 grms of the ketone. Reference is also made to Compte Rendus 141, 662 (1905) and Annale de Chemie ( 10 192 (1907)
I also again state that this rearrangement occurs when glycols are heated. Have a look at that thread.

[uemura]

twodogs,
thanks for posting the Houben-Weyl reference. Uemura will check it out, same for the "Li catalysed pinacol rearrangement possible?" thread. The Hoering - Ber Vol 38 Pg 3477 (1905) paper is the one Uemura first found and used for this thread. Carpe Diem

[halfapint]

The asarone ketone from the epoxide simply by heating, no acid present? Oxone!
turning science fact into <<science fiction>>

[uemura]

twodogs... The epoxide to ketone rearrangement by heating was discussed in a thread in Chemistry Discource called "Li catalysed pinacol rearrangement possible?"
Do you have the number for that post? Uemura's search hasn't been successful. Thanks Carpe Diem

[twodogs]

Uemura... The first post in that thread is

Post 218193 (missing)

(Ritter: "LiI catalyzed pinacol rearrangement possible?", Chemistry Discourse)

[uemura]

twodogs! Uemura apologizes his claim to have first submitted the thermal rearrangement rxn from epoxides to ketones. He just didn't catch the reference you have given in your post. Mea maxima culpa  

[sunlight]

Just heating the epoxyde or even de diol we get the ketone... Wow !!!
The literature says that KMnO4 in cold and neutral or basic conditions oxydize alkene to diols, but I've never seen it for safrol/isosafrol/asarone... Has it been tested ?
What about hidrohalogenation with sodium hypochlorite w/o strong acid ?
And other ways to produce the epoxyde ?

[Rhodium]

Yes, Ritter has tested the procedure (used the one from The Complete Book of Ecstacy) but he thought the solvent volume was impractical (and it cannot be made more concentrated, or the KMnO4 will cleave the side chain).

I don't understand why noone has tested the hypochlorite or hypobromite route to the halohydrin, and then made the epoxide from that with a base. It is OTC, and very simple.

[sunlight]

Mmmm, another time the volumes, shit.
Do you have any example of a halohydroxylation ?
There's another rxn that may be interesting, Milas hydroxylation, H2O2 and hv or Cr oxyde/Os/V in catalytic amount. Reference are from JACS 1936...1940, has anyone acces to them ?
Wich is the reason to start all these rxns with iso and not with safrol directly ?

[otto]

hi sunlight,

in answer to your last question: as long as you go via the epoxide there is no reason to start with the iso instead of the safrole since the 2,3-epoxide (formed from safrole) will give the desired 2-ketone, too. (ref: houben- weyl, vol. 7,2,a, p. 932; comptes rendues 184,1335,(1927))

otto

[sunlight]

Thanks otto.
I have still darks points about the subject, please see if you can clarify them.
I asume that peracid rxn with safrol gives "a complicated mixture of products".
Isosafrol diol, monoformyl glycol or epoxide rearranges to 2 ketone with H2SO4 or just heating (at least the epoxide), but what could happen with the diol or epoxide of safrol with the same procedure ? Would it be necessary to use LiI to rearrange the epoxide ?
Thanks.

[terbium]

Do you have any example of a halohydroxylation ?
Check out the Curriculum Vitae of this fellow, D.R. Dalton. Besides writing a book on alkaloid chemistry he has also written a number of papers on the preparation of bromohydrins/halohydrins using dimethyl sulfoxide as a solvent.

http://astro.ocis.temple.edu/~dalton/drdcv.htm

[otto]

hi sunlight,

using safrol in the performic will propably give the 2,3-diol, the formyl ester is easily hydrolised as soon as it gets in contact to aqueous medium. i doubt that you would get the epoxide.
concerning the rearrangement: i dont know wether the 2,3-diol will give the 2-ketone. what if not? i would rather expect the (3-arylpropionyl-) aldehyde to be formed.
the epoxide will certainly give the 2-ketone as literature says.

otto

[sunlight]

Very impressive !!!

[Vibrating_Lights]

Are yall saying that safrole con be put into a peracid oxidation and the resulting epoxide rearranged to MDP2P.  how would one go about seperating the epoxide from the other products.

[Rhodium]

Safrole can be made into its 2,3-epoxide in a number of ways (oxone or Acetonitrile/H2O2), but not a peracid reaction, which forms the glycol. If you make the 2,3-epoxide, it can be rearranged to MDP2P using LiI, LiBr and MgBr2 (among other reagents), but if it is subjected to the regular isosafrole treatment, there is a big risk that undesired aldehydes are formed instead.

[uemura]

Rhod,
You said

If you make the 2,3-epoxide, it can be rearranged to MDP2P using LiI, LiBr and MgBr2 (among other reagents), but if it is subjected to the regular isosafrole treatment, there is a big risk that undesired aldehydes are formed instead.

Do you mean by 'regular treatment' the rearrangement of the (2,3) epoxide using H2SO4? Or the whole peracid / rearrangement process applied to safrol?

[Osmium]

H2SO4.

[Vibrating_Lights]

So what we gonna do here is throw some iso into some DCM throw that in the bucket then throw some bleech in the bucket.  then take a big glass broomstick and start stirring.  whiles't yous's stirrin start droppin Hcl in.  when the cl that did not go into the dcm makes you feel like you gonna die you stop and.  then take your DCM layer and remove the DCM and then put the product in some acetone and a little water and some marble hest it a bit then extract with Dcm distill and reflux product with KOH to get the epoxide.  which an be rearranged with H2SO4.  That sounds more kick ass than a peracid.  how long yall reckon you would have to stirr the iso cl mix.

[Rhodium]

This sounds lethal.

[Chromic]

Rhod, it doesn't sound that bad. I think I'm going to try it (mind you, uhh... I think I'm going to try and use something more elegant than a bucket and a broomstick... lol), I'll let you know how it goes in

Post 236297

(Chromic: "anethole -> epoxide", Novel Discourse). I also wonder why no one has investigated this route... and I don't get why no one has investigated the route to the diol by slowly dripping in a concentrated solution of KMnO4.

[Rhodium]

Chromic: Your proposal sounds great, I was referring to VL's suggestion of mixing HCL and NaOCl in a bucket...

[Vibrating_Lights]

the remark about the bucket was going along with the mental picture that VL_ had of a one tooth hilbilly thinking he could make some drugs by simply reading this post and killing himself in the proscess.  This came right after a PM I recieved from someone who asked  "hey man i just want an ez recipee from sassafras to Mda in one pot with eazy to find chems and i already Utfse" .  you must notice the attempt at hilbilly dialect.
VL_

[Rhodium]

VL: Don't post aything like that int the future though, okay. We want no hillbilly syntheses around here.

[improv_chem]

Wow!  I just read this thread for the first time and It blew me away! 
So you are saying for sure that If you make the epoxide using say, Oxone/isosafrole,
you can re-arrange it to the ketone by simply distilling it!
That's one less step for SWIM's next dream.  Has anyone here actually done this?
Swim's a little paranoid because of chatter he's heard about epoxides exploading upon heating etc.
What you also seem to be discussing is the possibiltiy of skipping the making of isosafrole and just using your safrole in a Chromic's Oxone rxn or a peracid.
Two steps down would give a two step synth of MDMA from safrole with totally otc. stuff!
Keep it comming!!!!
-improv      
Let's play with nature a little, I'm sure we can make her a little higher....

[Chromic]

AFAIK, safrole will not work in a peracid reaction, I think VL got confused by what Rhod said. I will attempt the rearrangement of anethole epoxide (by forming it thru oxone) to anethole ketone by heat sometime in the near future and report back on it. If that succeeds, I may also try and form asarone epoxide again and instead of an 15% H2SO4 hydrolysis, I'll check out the rearrangement by heat for that compound. I wish I had dry bromine to attempt at forming the dibromide, although I'm sure my lungs are thankful that I don't.

[Vibrating_Lights]

I do not know for sure but i think the temp needed to rearrange the iso epoxide would also decompose it.  Not sure though.  if you try it watch for the temp to jump as the epoxide is converted.
Rohd Sorry about the hilbilly post  sometrimes i forget who all reads these.

[Chromic]

Btw, an oxone reaction on asarone was attempted. Although the H2SO4 rearrangement chewed the molecule apart, when NMR was run on the epoxide, it showed some interesting, but confusing info. It indicated that the methoxy groups were not cleaved by the oxone, and the benzene group was not affected either. It also showed that the E-olefinic group was gone, and it looked as if there was some E/Z action going on (chiral centers in the epoxide), but the multiplicity did not work out correctly (the hydrogen containing one of the epoxide links, alpha to the methyl does not have the correct mulitiplicity). Something odd is going on. I'm going to tell my friend to run an anethole/oxone reaction (which I know works) to figure out if the same sort of spectra is generated.

[uemura]

Good to know that such old stuff catches the interest of the hive bees .

Now, Uemura had a nice afternoon in his library and of course checked the Houben-Weyl reference which was provided by Otto. In the volume VII/2a Ketones, on page 934 he indeed found the section on thermal rearrangement. Unfortunately, the examples given there are not for asarone, but cite the experimental details of the Höring paper for isosafrole.

So, the precise mp of the asarone ketone is still a mystery and there is no literature reference so far what epoxide rearrangement method is applicable to arrive at it. Uemura, Chromic and hopefully other bees will continue to explore the possibilities to end up with the asarone ketone.

Nevertheless Uemura provides two tables from the Houben-Weyl section which talks about acid and thermal rearrangement of 2,3 glykols and epoxides. The Houben-Weyl is in German, but the tables shouldn't be a problem to be 'decoded'. There are also some non-german references Uemuras library doesn't have, perhaps some interested bee may consult the cited articles.



"Umlagerung" = Rearrangement
"Kochen" = "Cooking" aka Boiling
Carpe Diem

[cilliersb]

This just mean that you can follow the oxone route to Asarone Epoxide and do the rearrangement with ALCl3.

This = Ketone
Ketone + AL / Hg = Smangled beez!

HeHe

[Rhodium]

AlCl3 probably wouldn't be good, as it is such a strong lewis acid that it attacks the aromatic methoxy groups. You need to use a less active one, preferably LiI.

[cilliersb]

I can make My LiI from Li and I2 right, but how?

[Rhodium]

The direct reaction between the two elements are probably too violent and crude, so I would suggest that you slowly dissolve your lithium in methanol to form Lithium methoxide, and when it has all reacted and the solution cooled down, you add an equimolar amount of hydriodic acid solution (can be made from I2, see my page) dropwise to get a solution of lithium iodide.

Then the solvents are evaporated under vacuum in a flask situated in a boiling water bath to give crude lithium iodide. The lithium iodide is then recrystallized from boiling acetone (or from boiling water, using 0.5ml per gram LiI, followed by cooling in a freezer, preferably below -20°C to precipitate it all), filtered, and dried in a vacuum desiccator over phosphorous pentoxide for 1h at 60°C followed by 1h at 120°C (lithium iodide is extremely hygroscopic, so it must be rigorously dried to remove all the water).

Methanol is used to dissolve the lithium, because the reaction between lithium and water is too violent. The purification procedure is from a textbook, I don't know how much it can be simplified and still get a usable product. H2SO4 may substitute for the P2O5, and maybe the vacuum can be omitted, but I believe the dessiccator (or a ghetto version thereof) is a must. Could anyone comment on this idea?

[lugh]

Lithium iodide can be prepared in a quantitative yield by reacting iodine with lithium hydride in ether solution [JACS 77, 1507-8 (1955)]; lithium hydride may be formed by the action of molecular hydrogen on molten lithium [Ann Chim Phys 2, 273 (1874)], and may also be precipitated by the reaction between lithium methyl and triphenyl tin hydride in ethereal solution under nitrogen [JACS 75, 3592-3 (1953)]. Lithium iodide can also be prepared by more bee friendly but unreferenced methods ie neutralization of the hydroxide or carbonate with hydriodic acid, or by neutralization of lithium sulfate with barium iodide, followed by filtration of the barium sulfate.

[Rhodium]

Repost of an old Osmium post:


Asarone dibromide:

1) from asarone and Br2 in CS2
    Chem. Ber. 39, 1906, 2420
2) Br2 and CCl4
    Chem. Ber. 17, 1884, 1160
3) Br2 and pet ether
    Gazz. Chim. Ital 40 I, 1910, 114

Isosafrole dichloride:

1) CCl4 and Cl2
    Chem. Ber. 42, 1909, 263
2) Et2O and Cl2
    same ref.

Isosafrole dibromide:

1) Et2O and Br2
    Chem. Ber. 38, 1905, 2719
2) Br2 and pet ether
    Arch. Pharm. 248, 1910, 166
3) Br2 and CS2
    J. Chem. Soc. 105, 1914, 1971

[sunlight]

Lithium hydroxyde and lithium carbonate are not expensive.

[PolytheneSam]

>

Post 228375

(Ritter: "Re: Ketones from Propenylbenzenes via the di-bromides", Novel Discourse)

See US patents 3431068 5137700 5230879 3872220 6017500 and 6177589
http://www.geocities.com/dritte123/PSPF.html

[Rhodium]

Below follows the original literature which the following posts were based upon:

Post 227831

(uemura: "Ketones from Propenylbenzenes via the di-bromides", Novel Discourse)

Post 241293

(uemura: "Properties of some epoxides", Novel Discourse)

Post 243262

(uemura: "Epoxide Rearrangement Example", Methods Discourse)

Post 280991

(LaBTop: "Isosafrole Epoxide Thermal Rearrangement Review", Methods Discourse)


The first two articles are considered by the author to be Part I and II in this treatise on the reactions of propenylbenzene dibromides, glycols, halohydrins and epoxides and their transformation into the corresponding phenyl-2-propanones.

Zur Kenntniss des Anethols
Paul Hoering

Chem. Ber. 37, 1542-1560 (1904)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/hoering.anethol.pdf)
____ ___ __ _

Ueber die Oxyde von Propenylphenoläthern und die Umlagerung derselbern in die isomeren Ketone;
_{ein Beitrag zur Kenntnis der intramolekularen Wanderung der Atome}
Paul Hoering

Chem. Ber. 38, 2296-2299 (1905)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/hoering.epoxide2ketone.pdf)
____ ___ __ _

_{Ueber die Dibromide aromatischer Propenylverbindungen. III. Mittheilung.}
Ueber das Verhalten des Anethol-dibromide und Isosafrol-dibromids bei der Oxydation
Paul Hoering

Chem. Ber. 38, 3458-3463 (1905)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/hoering.dibromide-3.pdf)
____ ___ __ _

_{Ueber die Dibromide aromatischer Propenylverbindungen. IV. Mittheilung.}
Ueber Substitution und Abspaltung der Bromatome in den Dibromiden
Paul Hoering

Chem. Ber. 38, 3464-3476 (1905)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/hoering.dibromide-4.pdf)
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_{Ueber die Dibromide aromatischer Propenylverbindungen. V. Mittheilung.}
Ueber die Oxyde der Propenylverbindungen und ihre Umsetzungen
Paul Hoering

Chem. Ber. 38, 3477-3488 (1905)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/hoering.dibromide-5.pdf)