LUEshi is my god - 28-6-2005 at 11:39
I was just curious if there is a practical way (i.e. not requiring insane temperatures/pressures, or ~5% yield) to "de-phenylate"
phenylalanine?
Another idea that comes to mind is amination of propanoic acid. I know this is a really stupid question, but, looking for the most OTC route, would
oxidation of isopropanol give propanoic acid the same as oxidation of n-propanol, or is there such a thing as "isopropionic acid"?
Furthermore, could this "isopropionic acid" be aminated to alanine? Though I have no formal education in chemistry, nor much familiarity
with the nuances of organic chemistry, a hunch tells me that if what is stated thus far is true, isopropanoic acid would give one enantiomer of
alanine, and propanoic acid the other. Am I even close, or way off?
Just a few thoughts for which I hope to get confirmation.
12AX7 - 28-6-2005 at 11:43
Acid (COOH) only holds one bond, it would have to be isobutanoic acid or linear [2-hydroxy] propanoic acid.
Tim
LUEshi is my god - 28-6-2005 at 11:50
Hmm... so the basic idea would work, I'd just need to start from n-propanol rather than isopropanol, right?
Alanine
Kinetic - 28-6-2005 at 13:12
I'm afraid you're way off. Phenylalanine cannot be dephenylated by any practical route known to me, and a quick literature search pretty
much confirmed this.
Since alanine is so readily available, why don't you buy it? I can assure you it will be far easier than making it. You won't be able to
aminate propionic [propanoic] acid in the alpha position to give alanine directly. You could do it by a very roundabout route, but nobody in their
right mind would choose a several step synthesis, requiring not-at-all easy to get reagents to make something so readily available and cheap.
Propionic acid is also more readily available than 1-propanol, so you would never use 1-propanol to make the acid. The furthest you could oxidise
isopropanol (within reason, of course) would be to acetone, useless for any purpose in this context.
Your use of the word 'enantiomer' would be incorrect even if isopropionic acid existed. Enantiomers have exactly the same connectivity,
differing only in the organisation of the four groups around the central chiral carbon atom. So starting materials that are positional isomers would
not lead to different enantiomers of product, but instead products that are positional isomers of one another. Furthermore, the usual routes to chiral
compounds (that is, those that exist as enantiomers) will always give racemic products (a 50:50 mixture of enantiomers).
Here's a good site that deals with the concept of stereochemistry: Basic Concepts of Stereochemistry. Fortunately it also has the structures of each enantiomer of alanine, so you can see they are the
'same' (just mirror images of one another).
Good luck in your quest. Though you have a lot to learn, we all had to start somewhere.
Aspartame, a sweet-tasting dipeptide
Lambda - 28-6-2005 at 13:58
This artical gives some interesting historical information on high potency sweeteners like Aspartame.
http://www.chm.bris.ac.uk/motm/aspartame/aspartameh.html
The Dutch firm DSM is up to there neck involved in the Aspartame production. A young Dutch chemist nick named "Willy Wortel" couped up a
cheap way to make Aspartame. This process was an absolute boomer for DSM. Holland Sweetner Company (HSC) is a 50/50 joint venture of DSM and Tosoh.
(proud me)
[Edited on 28-6-2005 by Lambda]