synthesis of MD-A from Piperonal mixture - opinions, please!

joe_aldehyde · huxleys associate

some people may already have found an OTC source of piperonal in a mixture with another inert araliphatic compound. as i find it troublesome to either vac distill the mixture or remove the piperonal via its bisulfite adduct (which gives ridiculously low yields), i decided to try out to leave the mixture as is and thus mixed

25g piperonal + inert compound*
10g nitroethane
3g BuNH2
20ml IPA,

* (since piperonal is the main ingredient and i don't know the exact composition, i assumed that it is a 50/50 mix. of course it i not possible to determine yields this way, but i'm just trying to make a little fun stuff with no great hassle)

stirred vigorously and refluxed for 5 hours in a 250ml erlenmeyer. the mixture immediately turned piss-yellow upon addition of the amine catalyst. intermediate isolation of the nitroalkene is not possible due to its high solubility in the inert compound out of the piperonal mixture. the post reaction mix is dark red, so supposedly there are quite a few impurities present. i will try out different reaction times soon, but i could not do a shorter one for this time. since piperonal is more reactive towards nitroethane than plain benzaldehyde due to the electron-pushing nature of the methylenedioxy-bridge, shorter reaction times may well suffice.

how i'm going to proceed with this mixture:

the whole dark-red lot will be diluted with more IPA if the liquid is too sticky, put in an addition funnel on a 2-neck adaptor with refluxor connected to a 250ml erlenmeyer charged with a solution of NaBH4 in water (and a tiny little bit of NaOH). i will be using a twice molar excess of NaBH4 in the first run calculated to 100% of the theoretical yield of MDP2NP from a 50/50 mix of the starting compound. although there are presumably quite a number of impurities present, the color change of the solution will probably allow for the determination of the reaction progress.
after the NaBH4 reduction, the resulting nitropropane could theoretically be separated from the impurities by adding brine saturated with alkali, which will make a water soluble nitronate salt. a small part of the inert compound will also be present due to its slight solubility in water (about 10g/l H2O@20deg.c), but the impurities are hopefully going to stay in the organic phase.
it could well be that the solubility of the inert compound in both polar and non-polar solvents will carry some of the impurities to the water phase, and the nitronate to the organic phase, we'll see.
if this works out, the nitronate will be reextracted into a nonpolar (IPA?) with addition of dilute acetic acid, and this layer subjected to reduction with Zn/Acid (formic or hydrochloric?)

post your thoughts!

Star-light · Blacklight bulb

Probably you are having trouble isolating the nitropropene because of its impurities. This will cause it to fail to crystallize.

Use methylammonium acetate for 2-3 hours with a water bath temperature of 50C and you will get a purer product. Stick it in the freezer and it may well crystallize.

If you process your red mixture as you described you are probably going to get a lot of crap. I think you may be wasting your time. But then I have been proved wrong in situations like this before so go ahead if you fancy. It is just that you can normally bet on schemes like this not working properly. I certainly would not bother to invest my time in it because if you were able to isolate any product from the reaction your yields would be appaling. You need to get a purer product before reducing.

I think the water solubility of your inert substance is actually less than 1g per liter.

joe_aldehyde · huxleys associate

Star-light · Blacklight bulb

joe_aldehyde · huxleys associate

mk-1 · Sat Jun 25, 2005 8:01 am

Dear Joe,
Heres an excerpt (and a link) to some new article I found reporting the synthesis of PMA form Anise oil, without purification.
They go from undistilled Anise oil to PM-P2P and then to the amphetamine.
Check it out, as it may be valubale to ur research...