The Vespiary

The Hive => Serious Chemistry => Topic started by: pHarmacist on October 25, 2002, 10:21:00 PM

Title: New Route to MDA
Post by: pHarmacist on October 25, 2002, 10:21:00 PM
Cyrax: here is one more 'great' synthesis, maybe you can check it up in Vogel or elswhere to confirm its validity, i'm not being cynical...


(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000372654-file_mzte.jpg)

Note: in speed diagram, you can oxidize aldehyde directly to acid with some mild oxidizing agent such as Ag2O, instead of going tru NaBH4 --> alcohol ---> acid, we have to do that in MDA case since pi-bonds need to get reduced as well.

Never underestimate the power of retrosynthesis.
Title: New?
Post by: Ment2bee on October 25, 2002, 11:32:00 PM
I've seem something similar to this before.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/mda.dalcason.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/mda.dalcason.html)



And they tell me to UTFSE.

For that same great taste that'll always wire you up and never let you down, make it a dexedrine.
Title: Vogel and Advice
Post by: Rhodium on October 26, 2002, 01:38:00 AM
Pharmacist: Everybody has enough money to be able to read Vogel's. It is archived at

https://www.thevespiary.org/rhodium/Rhodium/chemistry/vogel3.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/vogel3.html)



Could you in the future please not post any total syntheses of psychoactive drugs without having any actual references for the reactions involved - especially not in this forum. Anyone here who has attended a basic college course in organic chemistry can draw a dozen of "possible reactions" leading to interesting compounds, but such schemes are of little use, as no directions at all are given about how to perform the reaction, do the workup, or purify the products - no hints of expected yields are mentioned either, something that is of utmost importance to gauge if a reaction is worthwhile or not.

Title: This time, I have no remarks from synthetic point ...
Post by: Cyrax on October 26, 2002, 03:20:00 PM
This time, I have no remarks from synthetic point of view.  OK, mabey one: K2Cr2O7 is some nasty shit.  Hexavalent chromium is highly carcinogenic, so using this reagent in the oxidation of [3] is not advisable.  But for the rest, everything looks just fine.
Title: More easy!
Post by: Tricky on October 26, 2002, 05:37:00 PM
pHarmacist, 2-phenylpropionic acid may be produced more easy:
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000372654-file_2dve.gif)
Check out:

http://www.orgsyn.org/orgsyn/prep.asp?rxntypeid=20&prep=V76P0169 (http://www.orgsyn.org/orgsyn/prep.asp?rxntypeid=20&prep=V76P0169)


Good Luck.

Wanna make laugh the GOD? - Tell him about your plans.
Title: Tricky, I think your proposed synthesis will not ...
Post by: Cyrax on October 26, 2002, 06:37:00 PM
Tricky, I think your proposed synthesis will not work.  In order to make a compound like [4] (in the synthesis of pHarmacist), we need to prepare a 2-benzylpropionic acid instead of a 2-phenylpropionic acid.

There is a significant difference in the reactivity of Ar-CH2CN and Ar-CH2CH2CN

If you look at the proposed reaction mechanism, you see that the base (K2CO3) abstracts a proton from the benzylcyanide, and the resulting carbanion reacts with the dimethylcarbonate.  The carbanion is stabilized by 2 electron sucking groups, hence it can easily be generated by a weak base.

With Ar-CH2CH2CN, it's a whole different story. 
First, you will need a far stonger base to generate the carbanion since the carbanion is only stabilized by one electon sucking group (K2CO3 will not work). 
And second, the place of proton abstraction is ambivalent.  Which proton will be abstracted?  The one from the methylene next to the aryl group, or the one from the methylene next to the cyano group.  I think both reactions will take place, especially if the base is strong enough.  You would need information about pKa of the protons on the methylene groups of Ar-CH2CH2CN, in order to devise a selective reaction (chose the right base).
Third, it is likely that the required stong base will react with the dimethyl carbonate.
Title: Sorry...
Post by: Tricky on October 26, 2002, 06:38:00 PM
about above topic...
it's my great mistake... :(
I've just confused 2-benzylpropionic acid with 2-phenylpropionic... fuck... it's visual fiction...
one more sorry

Wanna make laugh the GOD? - Tell him about your plans.