09-25-01 04:16
No 216888
Since acetone is essentially a ketone (double bonded oxygen across carbon chain), I wonder if you could form the imine by reacting bromo-acetone with methylamine, then reducing that to the corresponding methyl-amino structure. Then when the grignard is utilized, instead of forming p-2-p at the end, it would form meth. Hmmmm, the possibilities are endless!
hatred of ontological wastes, and the marathon!!!!
(Hive Addict)
09-25-01 06:45
No 216943
won't work
(Hive Bee)
09-25-01 07:17
No 216949
Grignard reagent of an amine cannot be prepared. Besides, I don't think anyone is going to want to work with Bromoacetone. It's bad even with a good fume cupboard.
06-12-02 22:13
(Rated as: misinforming)
(Chief Bee)
06-13-02 00:37
No 320455
Whizard: WRONG! A protonated amine would inhibit the grignard formation even more.
(Hive Bee)
08-01-02 12:40
No 339768
why wont it work?
hatred of ontological wastes, and the marathon!!!!
i cook to save the planet!!
(Chief Bee)
08-01-02 14:08
No 339788
R-MgCl + R-NH2 -> R-H + RNHMgCl
A grignard reagent encountering a labile proton as in NH2, OH, COOH etc gives the corresponding hydrocarbon of the grignard reagent, and the magnesium salt of the other compound.
(Stranger)
08-01-02 21:32
No 339884
Then how about Br-CH2-CH(NHCH3)-CH3 + Ph-H =AlCl3=> Ph-CH2-CH(NHCH3)-CH3?
That is, friedel crafts alkylation with the bromoisopropylmethylamine with benzene? If one uses a huge excess of benzene it should be possible. I've seen a similar procedure on Rhodium's page...
I don't see how the methylamine would NOT react Sn2-style with the bromoacetone forming a-methylamino-propylketone as well as by reductive amination with the ketone in the first place, though...
Stanley
(Chief Bee)
08-01-02 21:52
No 339893
Br-CH2-CH(NHCH3)-CH3 really looks like something waiting for polymerization, especially together with AlCl3, the alkyl bromide part going SN2 on the nitrogen. Where is the similar procedure on my page?
It is possible to perform a friedel-craft acylation with N-methylalanylchloride (like the compound above but with -COCl instead of -CH2-Br) if the nitrogen has been protected as an amide and a mild lewis acid is used, to form the corresponding N-protected methcatinone, which can be reduced and deprotected to the amphetamine. Nichols et. al. uses that technique for stereoselective syntheses of difuranylamphetamines.
(Stranger)
08-01-02 22:07
No 339896
Would it polymerize even when very diluted and with a huge excess of benzene, and perhaps a milder lewis acid? I'm sorry, I refered to the FC-alkylation whit chloroacetone on benzene - I guess the similarities are quite few
That sounds like a better way to go. But the product should be _meth_amphetamine, yes? Or it's just me being delirious again
This piece of text has been added post-posting:
One might want to synth the HCl-salt of bromoisopropylmethylamine, which won't polymerize, and in my eyes it won't hinder the FC-reaction either... I'm thinking about my jar of bis(2-chloroethyl)amine, which would definately polymerize if it wasn't the HCl-salt.
Stanley
(Chief Bee)
08-01-02 22:17
No 339901
FC alkylations require strong lewis acids, while FC acylations can make do with milder ones.
Yes, very diluted you might get A yield, but I'm afraid it is not anything that is usable in practice. Ever noted the wonderful 32% yield with chloroacetone?
Yes, I meant methamphetamine, I was just saving a few electrons by not typing out the whole name
02-19-03 03:01
(Rated as: insignificant)