Jubrail (Hive Bee)
05-30-02 21:04
No 316013
      MDMA through photomethylation of isosafrole  Bookmark   

I found this on Rhodium's site at ../rhodium/chemistry /photoamination.html

Proposed experimental method.
Proposed procedure of photomethylamination of isosafrole. Into a Pyrex vessel was introduced an MeCN-H2O (9:1, 70 mL) solution containing isosafrole (C10H10O2; 0.567 grams, 3.5 mmol) and DCB (3.5 mmol). The solution was then saturated with methylamine gas. The solution was irradiated by a 300-W high pressure mercury vapor lamp under cooling with water. Upon completion, the solvent was stripped in vacuo, and the residue was washed an aqueous 10% NaOH solution, and extracted with DCM. The DCM was stripped in vacuo, and the oil distilled in vacuo, yielding the free base of MDMA. The base was disolved in dry Et2O, and dry HCl gas was bubbled in. The precipitated crystals then dried, weighed, and tested for biological activity.

Has anybody tried anything like this before?  The theory behind it seems solid, but will the yields be worthwhile?  What would one have to look out for to make sure the synth doesn't get fucked up?  Where and for how much could one get a mercury lamp?

Or is this simply one of those methods out there that is really interesting but would cost a lot of cash in trial-and-error to get down?

Rainbows & Butterflies Forever :)
(Hive Addict)
06-01-02 07:18
No 316569
      Interested  Bookmark   

Swims been interested in it for a while.  however he can not obtain P-DCB. A different photocatalyst needs to be found. The role of the DCB is to hold onto the electron that is emmited from the alkene long enough for the MeAm to complete a neucleophilic attack on the alkene. The high intensity light causes the loss of the electron.  I suspect DMSO could be a suitable solvent as well.  Rxns can be carried out in a solid state withthe proper catalysts.  It is very important to use a quartz vessel cause standard glass is slightly opaque to the light.
Good luck.
06-01-02 20:59
No 316705
      other catalysts for photoamination  Bookmark   

While m-, and p-dicyanobenzene are somewhat difficult to obtain, what about other related compounds? The reason that DCB's are such good electron acceptors is that any added charge is delocalized throughout the benzene ring. On top of that, the nitrile groups are strongly electron withdrawing, thus reducing electron density on the ring, making it easier for the ring to accept that extra electron.

So, you need to find something analagous to m-DCB, but a bit more ubiquitous. You need something that can accept a free electron, without irreversibly reacting with anything because of it. You'll need something aromatic to get that delocalization effect, and also some electron withdrawing groups on it for stabilization. As it turns out, m- and p-dinitrobenzene (DNB's) fit this description perfectly, and are used industrially for similar purposes. DNB is commonly used to stop free-radical chain reactions in polymer syntheses. In the industrial case, DNB's are added to scavenge for free electrons, essentially putting an end to any chain reaction that involves them. In the case of DCB's and photoamination and DNB's and free-radical inhibition, the catalyst performs the same task -- temporarily holding onto electrons to affect the rate of reaction.

BTW, DNB's are very cheap, as you may expect (after all, how difficult is it to dinitrate benzene?)

I've often wondered why Masahide Yasuda never published photoamination experiments using any catalysts other than DCB's. I have a feeling he may have looked into this earlier in his career, but I haven't found any article on it yet. I have his phone number laying around somewhere, and I've often thought about giving him a call to discuss this with him. However, as soon as I start making plans for this in my head, I remember that I have the common sense to know that I shouldn't harrass the poor slob. Its just one of those basic rules of life: never stalk obscure Japanese chemistry professors, unless you have a really good reason to.
(Hive Bee)
06-02-02 01:11
No 316768
      Obscure Chemist.  Bookmark   

Anton, The aforementioned professor, might be happy to talk/write to you.

One of my obscure college professors, when he was puzzled, would call up and query..... Linus Pauling.

Pauling was quite happy to confer with him; he liked a stimulating conversation, wherever it came from. Pauling was a chemistry teacher, and he admired chemistry teachers. If a chemistry teacher could track him down, Pauling would talk a while. They shared a mutual interest, and Linus didn't suffer from self awe..... He was a regular guy.

Yasuda, might be a great guy, laboring away in obscurity... while teaching "Intro. to Chem." to bored business majors.

A little genuine admiration and enthusiasm, could brighten his otherwise dreary day. Even better, maybe your local U's library, contains expensive periodicals, Dr. Yasuda has no easy access to. There are some shared interests, it is not impossible, you and he might become friends.

In short, Dr. Yasuda, might feel honored if you stalked him a little bit.

So, how is your Japanese?
(Hive Addict)
06-02-02 03:09
No 316785
      Safety info for DNB  Bookmark   

DOes any one have any comments reguarding A prpopsed method for seperating amine from a rxn mix.  For instance lets say the rxn is run isosafrole and DNB are dissolved in dry dmso and chilled to 5.c in a seperate container Anhydrous MeAm is gassed into chilled DMSO at a rate of 10mol per mole of alkene.  the two are combined in a quartz vessel in an ice bath. SOlution is irradiated.  following the rxn the MeAm is distilled off into HCL then the dmso removed under vac. 
1.  Are ther any dangers in having the DNB in high concentration with the amine at the end of the MeOh distillation.
2.  Will the dnb follow the amine through a typical A/B.
3. would it be best to first acidify and wash with dcm before basification and extraction.
4.  Would the DNB react with the hcl would dcm extract the DNB
5. what is the best way to seperate DNB and Amine.