wacko_reaco (Stranger)
07-30-01 23:08
No 200211
      mda review/questions  Bookmark   

I am hoping to generate a kind of mda from mdp2p review, so any comments or further qustions would help this thread enormously. The reason I want to start this thread is the kind of difficulty experienced in obtaining cyanoborohydride (it is listed on two prohibited registers where I come from, poisons and drug manufacture)
So as far as i can glean from all available sources the only route to mda from md2p2 is via the imine/cyanoboro/AA or (NH3) (the sodiumborohydride method doesn't work, don't anyone try to convince me as I have the lab yards to prove it, best yeild was ~10%) or via the leuckart using formamide to form the amide then acid or base catalysed hydrolysis. The methods are all in other places so i won't repost them. The questions I have are as follows
-If the cyano works then this means that the imine does form with ammonium acetate as the hydride reduces the imine. This implies that the sodiumborohydride method does not work because the reductant is either not strongly reducing enough or kinetically too slowly reducing and the imine irreversibly reverts to the alcohol. Does this logic seem sound?
-The leuckart yeilds seems awful, around 30% (from ketone to amine) does anyone have any yeild breakdowns from the amide formation and then the amide hydrolysis?
-Is there a method I have missed, the obvious one is from bromo/iodosafrole using the bomb with hexamine and/or meAm, but I have not seen any relaible results/reports from that method so am loath to advocate it.
Anyway here begins hopefully a fruitful discussion.

wacka wacka wacka
 
 
 
 
    Rhodium
(Chief Bee)
07-31-01 03:31
No 200257
      Re: mda review/questions  Bookmark   

../rhodium/chemistry /mda.azide.html

Bromosafrole is formed, and it is then swapped with azide with a PTC, and then it is reduced in a two-phase reaction with NaBH4 and a PTC. It's all a one-pot reaction.
 
 
 
 
    tecnetium
(Hive Bee)
08-02-01 02:26
No 200761
      Re: mda review/questions  Bookmark   

Hi wacko. Before the hive went down I seem to remember a post about MDA- using NaBH4 (I think). In that thread a few bees mentioned that the pH had to be maintained at 7.0 to avoid the reduction of the imine to an alcohol- I've tried to find that thread since and cant seem to locate it. Have any bees heard of this?