fraggle
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reduction of MDP2NP
Hi Guys , I have been reading these fora for years and have learned a lot. Having been uninspired by bad teachers I came to chemistry late in life
and having not paid as much attention as I should have at school have come across a problem right at the end of an experiment that is probably quite
basic so please humour me.
I decided to try a total synthesis and to make a gram of MDA for analytical purposes without passing through the more common routes and because I am
interested in how the reaction works rather than becoming a drug lord I decided to ask your opinion. I am sure that you are told a million times by
tweakers that they are ,not tweakers but so far to get to my 1.1 grams of MDP2NP from black pepper my products alone have cost three times as much as
purchase price from a dealer in the UK.
I followed " the cooks " pepper to piperonal synthesis which went very well until the permanganate oxidation which from all accounts she also found a
bit of a trial but decided to use hot H2O to melt any formed piperonal from the chocolate brown gunk which could then be filtered 3 times removing the
melted piperonal crystals from the black manganese dioxide powder. This left me with a "dirty water " coloured suspension which was evaporated
leaving light tan crystals which when washed in hot acetone left off white piperonal crystals.
These crystals weighed 1.4 g
From here I followed Rhodiums MDP2NP from piperonal synthesis using .7g nitroethane in an icebath with manual stirring due to last stirbar accidently
going going down the sink on a holiday weekend. Upon reaching the addition of the HCl the colour change mentioned in the synthesis happened exactly as
described. A friend said that this is typical of the methylenedioxynitropropene synthesis and is not to his reportedly small experience ( P2NP )
something that happens in all syntheses involving nitropropenes. Having read Dal Casons routes to MDP2P I decided to try zinc in acetic acid. This is
where the lack of attention at school chemistry seemed to cause a problem. My friend told me that iron powder reduction could be too violent for the
MD ring and that the zinc would be better.
Having added the molecular equivalent of acetic acid to reduce the zinc powder I added the nitropropene and gently reflux with swirling for 80 minutes
until the zinc had all but disappeared and the smell of acetic acid had been replaced by a sweet smell that I can not describe but the best I can get
is a sort of fruity alcohol. The yellow solvent was full of small yellow snow flakes which I took to be the acetate salt of the product but I maybe
wrong. These were basified with NaOH where they formed a red/orange oil. This oil was extracted in toluene and separated and acidified leaving me with
about 20mg of product which when the salt NaCl was cleaned out left about 12mg of crystals which was such a bad return from the nitropropene that I
had more questions than answers. I have photographs of each stage and would appreciate your input if anyone can advise. I am presently ready to redo
more MDP2NP and its heart breaking to see a weeks work fall at the last hurdle.
My question is would I be better to use Hg/Al to reduce which I have used many times but thought that it would not be worthwhile with such small
amounts or am I doing something wrong with the Zinc / Acetic?
Thanks in advance for your help. Your site is much more interesting than High school ever was.
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azo reborn
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first there are many reductions of nitroalkenes
ex nitroalkene to nitroalkane
nitroalkene to ketoxime
nitroalkene to ketone
nitroalkene to aminoalkane
nitroalkene to hydroxylamine
what is the desired end product
regards azo
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fraggle
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Thanks Azo for your reply. I am trying to get to get to the aminoalkene. I know that the zinc/ acetic can be used succesfully to reduce nitro alcohols
but this one has me a bit stumped due to terrible return really in the last A/B
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UKnowNotWatUDo
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Do you mean the aminoalkane?
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fraggle
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sorry I meant the alkane.
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UKnowNotWatUDo
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No worries, we all make typos. I have never run this particular reaction but from what I've read and seen I would try an iron powder reduction in
acidic media if zinc/acetic isn't giving you good results. Keep in mind that an iron powder reduction will give you the ketone. However it sounds like
some of your nitroalkene is bring reduced to the ketone anyways. Did you check the organic layer for ketones? You may also want to make sure you are
retrieving all of your product in the workup (multiple washes, etc). Sorry I can't be of any real help, as this is all just speculation. Good luck.
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azo reborn
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hi fraggle the reduction to the amino alkane is not very easy to acheive generely the oxime is formed unless you use reducing agents like vitride or
lah or cth the best way for a back yard chemist is to reduce to the oxime first then to the amine or reduce to the alkane and then reduce the nitro
group basicly to steps the nitroalkane can easily be reduced with tin and hcl
regards azo
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fraggle
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Thanks a lot. So the iron will not cause a problem for the methylenedioxy ring?
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UKnowNotWatUDo
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I wouldn't think so, but again I've never worked first hand with this compound or any of it's derivatives. Try substituting the zinc powder for
cleaned iron powder and perform the reaction again as before in glacial acetic acid. I usually run small scale versions of reactions I'm studying and
vary the conditions (time, temp, pH, etc) and a clearer picture starts to form. That's just me though.
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fraggle
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Thanks for all the help guys. I especially like the idea of reducing to the nitropropane first. I didn't give it enough thought at first that by
adding the extra step it could improve the yield. could I ask if anyone has an RF for either the nitroalkane or or the ketone so I can check for
impurities or finished reaction. Thanks again.
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turd
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Honestly, if I were you, I would first optimize the whole pepper to MDP2NP route before proceeding (IIRC there was recently a thread by Antoncho on
this subject). 1.4 g may be OK for a lab with the proper equipment and technique, but in a home setting this will be tough. Especially it does not
give you any possibility to optimize reaction conditions. Your only hope is to follow exactly a published procedure for your substrate.
If this doesn't work out try another route. I'm sure it's doable from benzodioxole. 5-bromo-1,3-benzodioxole is commercially available so can be made.
My first idea would be to do a Grignard on that with DMF. Don't take my word on it though - check the literature. (Finding a library with
Scifinder/Beilstein access should actually be the very first thing to do - if you didn't already)
As to reduction - I'm quite sure that Al/Hg would work. I've only used it on nitrostyrenes and never on nitropropenes, but see for example #3 here:
http://www.erowid.org/archive/rhodium/chemistry/nitrostyrene...
Yields are not high, but at least it never failed on me. This is a tractor of a reaction.
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Nicodem
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Quote: Originally posted by fraggle  | This left me with a "dirty water " coloured suspension which was evaporated leaving light tan crystals which when washed in hot acetone left off
white piperonal crystals.
These crystals weighed 1.4 g |
And what was the melting point of these acetone insoluble crystals?
| Quote: | | Thanks in advance for your help. Your site is much more interesting than High school ever was. |
Maybe, but if you had listened your teachers in the high school, you would've learn that a scientific discourse is based on references (coincidently
this forum is a science forum!). Sadly, your posts contain none, even though they should contain plenty to be comprehensible enough for a thorough and
reliable answer. Next time, if you feel too lazy to include references, open the thread in the Beginnings section where I'm moving this one too. And
if you have an urge to convince us that you are so different from tweakers, then at least have the decency to use chemical nomenclature rather than
slang codes!
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Nicodem
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Thread Moved
14-11-2011 at 12:38 |
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