slowone
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More microwave cth questions...
Hi all, i've been reading this place for a while and i think that its great! Unfortunately i'm shit at chemistry so it takes me a while to understand
things, i'm getting there but its hard going for me. I'm a biology student at uni in the UK and i try to stick to what i'm good (read: decent) at.
Well anyway, i'm terribly interested in microwaves as they seem so much easier and require much less equipment than most other methods.
What i'd like to know is if its possible to do the CTH (of ppa) in a microwave without forming an ester first? There are a few refs from rhodiums
archive:
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Reduction With Palladium--Ephedrine and Phenypropanolamine with HCl (Gas) Reduced to Methamphetamine and Amphetamine:
Metzger, Bases of the 1-Phenyl-2-aminopropane Series, German Pat. No. 968,545, Mar. 6, 1958; C.A. 54:7654b (1960). 1-Phenyl-2-methylamino-propan-1-ols
were catalytically hydrogenated in the presence of palladium, glacial acetic acid and dry hydrohalide gas.
60 g d,l-ephedrine hydrochloride in 600 cc glacial acetic acid containing 30 HCl gas was hydrogenated at 90° in the presence of 50 g palladium black
(note: this is a very high catalyst ratio), the catalyst separated, the solvent evaporated, and the residue made alkaline to give 95%
d,l-deoxynorephedrine. Similarly prepared were D-deoxyephedrine (d-methamphetamine) and D-deoxynorephedrine sulfate (d-amphetamine).
Note that there is evidently an error in the Chemical Abstracts translation. Reduction of ephedrine would be expected to give deoxyephedrine;
reduction of phenylpropanolamine (norephedrine) would be expected to give deoxynorephedrine. |
Only i was thinking about using the ammonium formate/ PD/C 10%/ etheylene glycol method.
So what do you all think?
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jon
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you would'nt be able to use a formate in that scenario in the prescence of a strong acid all you would get is it's conjugate base pair and formic
acid, and formic acid needs to be buffered in these reductions.
the strong acid (hydrogen chloride gas) in this case forms the CCl bond insitu and this gets reduced, it's damn difficult to reduce COH groups
directly.
I don't think you can skip the derivitization step on that OH.
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slowone
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Boo, how dissapointing, well thanks for clearing that up for me!
(by the way i still didn't understande half of what you said!  )
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slowone
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Acually now that i've read this again (sober) that i think you were talking about the first reaction scheme? I don't want to use that method. I want
to use ammonium formate as a hydrogen donor in presence of PD/C heated in the microwave in ethylene glycol.
Can this be done before forming the ester? ie chloro, bromo, iodo ephedrine etc?
Does anyone have anymore input to set me right?? U2U or otherwise.
Thanks and apologies if i sound stupid
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jon
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nope
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contrived
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could he do a reductive amination using P2P, MeNH2 and the reagents he porposed? in the MW?
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