Thanx foxy.
I have another series of interesting questions. (well I find them interesting
)
PrimoPyro is now interested in the hypothetical synthesis of ephedrine-like compounds. Specifically 1-phenyl-1-hydroxy-2-amino-propanes. This should be no big issue, until:
Im trying to find a synthesis route from the propenyl-benzene. On top of that, the product has to be the correct chirality for an oxazoline cyclization. Now to be honest, PP never put too much interest in learning chirality. I get the concept, but some of the terms evade me. I know what the difference between different isomers of ephedrine are, but I cant name which is which, the names escape me. So, that said, bear with my alternative language for them in this post. Thank you.
Now, I assume that the needed configuration is between the hydroxy and the amine for cyclization. I assume they need to be near each other, to be in proximity. this would denote a sort of cis isomer right? I dont think you name optical isomers this way, but I am here anyway. So, assuming what I have said thus far is ok, I would like to propose this:
The propenylbenzene is epoxidated, then reacted with hydrobromic acid to open up the epoxide to the alpha-hydroxy-beta-bromo-propane. This is then aminated with ammonia to form the 1-OH-2-NH2-propane.
I would think that the epoxidation would occur, having the correct bonding, as stated as having been needed above. (cis) as trans bonding would have a longer stretch on the oxygen bond and be less stable, or it would simply cause torsion in the C-C bond to revert to the stated "cis". Forgive me its hard to explain myself without a lot of pictures. Let me know if this is totally not understandable and I will draw some up.
Since this epoxide should be the correct configuration, so would be the products upon opening it up.
But, I wonder, could the 1-bromo-2-hydroxy-propane be a byproduct? I remember reading old ADC posts awhile ago stating that HBr only adds to the beta carbon in safrole, but I wonder if this is only applicable to alkenes.
If this step worked as well, when you aminated with ammonia, the hydroxy and amine groups would be in the assumed correct positions for cyclization.
I'd like to hear any questions on this, as well as many bees comments on anything posted herein. Thank you.
P.S. buying the correct isomer is not an option. This topic is about the synthesis of such a compound, so while all pointers on where to buy or extract this from are a nice thought, they arent the desired information.
Also, I have only presented here what I thought of in my head, id like to know if it will work etc., but I also want to know of any known syntheses of such compounds, or any known similar reactions that come to mind. It doesnt HAVE to be regarding this synthesis. Thanx again.
PrimoPyro
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