WHITE_DEVIL (Newbee)
10-29-02 12:18
No 374180
      idea for bromosafrole => mda  Bookmark   

This sounds so simple that im sure it cant work but here goes:

bromosafrole + NaNO2 => 3,4-MD-phenyl-2-nitropropene + NaBr

3,4-MD-phenyl-2-nitropropene is then reduced to MDA
 
 
 
 
    Rhodium
(Chief Bee)
10-29-02 13:57
No 374242
      That reaction qould be very low yielding, if ...  Bookmark   

That reaction qould be very low yielding, if nitrite at all would react with a secondary halide - and if it would, mostly the nitrite ester would be formed. Swap bromosafrole with azide instead, with that almost quantitative yields are possible.
 
 
 
 
    WHITE_DEVIL
(Newbee)
10-29-02 14:31
No 374256
      Sorry Rhodium i dont quite follow.  Bookmark   

Sorry Rhodium i dont quite follow. Do you mean react sodium azide with bromosafrole. or fuck bromosafrole right off and actually start with 3,4-MD-phenyl-2-azidopropene. how would you go about doing this?
 
 
 
 
    Rhodium
(Chief Bee)
10-29-02 17:26
No 374311
      The Azide Route  Bookmark   

I meant:

Safrole -> Bromosafrole -> Azidosafrole -> MDA

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

Also UTFSE for azide and bromosafrole.
 
 
 
 
    pHarmacist
(Hive Bee)
11-01-02 07:42
No 375384
      bad leaving group  Bookmark   

Generally halo atom on safrol is a bad bad leaving group, however, wouldn't it be more conveniant to simply "oxymercurate" safrol to corresponding sec. alcohol, followed by mesylation, that would convert OH (bad leaving group) to one of best leaving groups, this can then be attacked by a nucleophile such as methylamine in sn2 fashion... the only problem is if not 2 different mechanisms (sn2/E2) will take place one (sn2) leading to MDMA and (E2) leading to isosafrol + H2O :), this of corse can be controlled (kinetic/thermal) controll.... i dunno, just a thought..

Never underestimate the power of retrosynthesis.
 
 
 
 
    Rhodium
(Chief Bee)
11-01-02 09:42
No 375410
      Generally halo atom on safrol is a bad bad ...  Bookmark   

Generally halo atom on safrol is a bad bad leaving group

Why? With a PTC you can get close to quantitative yields in the SN2 rxn between azide and bromosafrole.

wouldn't it be more conveniant to simply "oxymercurate" safrol to corresponding sec. alcohol

It works, but I would hardly call that route more convenient in any way, also you need a stoichiometric  amount of mercury salt when oxymercurating safrole, which is almost twice the weight of Hg salt to safrole.