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reductive amination using magnesium metal

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Author	Topic: reductive amination using magnesium metal
rev drone Member	posted 03-17-99 11:25 AM I haven't seen this article before, but here it is. Some interesting research out of Yugoslavia: magnesium seems to be a great way to go. They did reductive aminations with all sorts of different ketones and amines, and they were able to yield methamphetamine in 80% yields (99% purity). Reagents: nothing but the ketone, the amine (or ammonium acetate in the case of making benzedrine), some MeOH, some AcOH, and of course, Mg metal. room temperature, stirring, 12 h. J. Chem Soc. Perkin Trans. 1, 265-269 (1996) ------------------ -the good reverend drone
Semtex Enigma Member	posted 03-17-99 11:37 AM Sorry Rev, I can't look that up for a while, is it also done at atmospheric pressure?
rev drone Member	posted 03-17-99 11:41 AM Absolutely, it is done at atmospheric pressure. ------------------ -the good reverend drone
placebo Member	posted 11-11-1999 04:59 PM Rev drone, any developments in this area? I have been on this damn search engine for days...this still looks good but I need some more details, so one would need: MDP2P Methanol Acetic acid (should it be glacial?) methylamine, Hcl or gas in aq.?? Mg, metal turnings H2 gas, pressure is no prob if it helps! Could anyone state figures in gms, and comment on dreams and yields?? Has anyone dreamed it? I have read an old thread where eigenfxn had some dreams but its more confusing then anything! Any comments? ------------------ Placebo.... Remember it's all in your mind!
Huffalump Member	posted 11-11-1999 06:01 PM On the subject of magnesium... They sell tinderkits that consist of a flint attatched bar of magnesium about 3.5" x .75" x .25" for around 6 dollars in the camping supply section of whatever store you may chose to go to. I haven't gotten one in about 7 years now, but I don't see why they'd stop selling them. Alas, I don't know if it's pure magnesium either. I suspect that it may very well be. Huffalump
psychokitty Member	posted 11-11-1999 06:48 PM I would say that without a doubt, you would have to bubble anhydrous MeNH2 gas into the methanol in order to get good yields. But this isn't at all hard to do, or so many bees have claimed. --PK
Slappy Member	posted 11-11-1999 07:00 PM Drone: Actually, the article is from 1995. Rhodium has had the Perkins Transactions article up for many months. It certainly does look good. I wonder, as I'm sure Drone does seeing as though he has brought it up so many times, why this has not become the preferred method of reductive amination? Al/Hg sucks big time. Mercury sucks some major ass, and Aluminum sucks. C'mon guys, what's up? This method is the best thing to come along recently, especially considering that it's pretty much OTC. http://rhodium.lycaeum.org/chemistry/pictures/mg.redamin.1.gif http://rhodium.lycaeum.org/chemistry/pictures/mg.redamin.2.gif http://rhodium.lycaeum.org/chemistry/pictures/mg.redamin.3.gif Hint- go to machine shops where they work with Al and Mg, and tell them that you're looking for Mg turnings. They should have drums full of them that they'd be more than willing to sell to you for practically nothing. But then again, do you really need to go to that much trouble to get Mg?
Slappy Member	posted 11-11-1999 07:06 PM I forgot to mention how much I hate JCS journals. They are too god damned big to fit on the photocopier. What's with that? I though 81/2"x11" was pretty much and international standard. Oh well, leave it up to the Brits to screw everything up.
placebo Member	posted 11-12-1999 06:05 AM Aquisition of Mg is not the problem nor any other reagents/catalysts or solvents. One would just like a briefly written synth to follow and some comments on yield etc. Anyone? Please! ------------------ Placebo.... Remember it's all in your mind!
Niels Bohr Member	posted 11-12-1999 12:47 PM Hey Slappy - if you haven't already thought of this; reduce the copy size, lay the fat ass journal with both pages in the exposure area, press lightly on the binding, and get two bangs for your nickel! Only good if you have good eyes or good reading glasses.
Slappy Member	posted 11-12-1999 11:14 PM Niels- Unfortunately, the dumbass copiers (IKON) on campus all have a restricted exposure area. JCS journals just won't fit in the exposure area, they are too tall. placebo- Are you blind? I gave you the links to the journal article. Can you not interpret scientific literature? Well, here is the procedure anyway... quote: "In a 250cm³, single-neck flask were combined 4-phenylbutan-2-one (7.41g, 50mmol), AcONH4 (38.54g, 500mmol), Mg (6.08g, 250mmol) and 70% aqueous MeOH (100cm³). The flask was capped with a mercury-filled bubbler, to reduce escape of NH3, and the mixture was stirred at 20-25°C, for 12h. If the reaction was not complete (TLC), additional AcOH (6.0g, 5.70cm³, 100mmol) and Mg (2.43g, 100mmol) were added and the stirring continued for an additional 12h. The mixture was poured into water (600cm³) to which NaHCO3 (50g) was then added; the whole was then internally steam distilled until 500cm³ of the distillate collected. It was made alkaline (pH > 12) with 50% aq. NaOH, and extracted with CH2Cl2 (3x50cm³). The combined extracts were dried (K2CO3), filtered and evaporated on a rotatory evaporator. The residue was dissolved in MeOH (20cm³) and added slowly, with stirring, to a solution of anh. oxalic acid (5.40g, 60mmol) in MeOH. Complete precipitation was effected by adding Et2O (50cm³) to the mixture and cooling it to -20°C. The yield of the mixed monooxalate salt was 8.63g. An analytical sample of the free amine was obtained as for 3a: purity (GC): 90% of the primary amine and 10% of the secondary amine. The pure primary amine was obtained by vacuum fractional distillation: bp 90-95°C/10 Torr; yield 3.71g (50%)" Just substitute MDP-2-P for 4-phenylbutan-2-one, follow this procedure, up to when they collect the freebase, and then just salt it as you normally would (i.e., HCl instead of Oxalate). Yields would be much better using anh. MeNH2 in MeOH, around 60-80%.
homebrew Junior Member	posted 11-13-1999 02:51 AM One thing this Bee can say about this method is DO NOT PUT ALL METAL IN AT ONCE:::::::: CAREFULLY ADD; SLOWLY: or you get the flask emptied for you asap....

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