Sciencemadness Discussion Board

Benzaldehyde from phenylalanine

cal - 24-2-2012 at 16:58

I have found many references to this but, Has anyone actually tried it and has a detailed synthesis.


If you want a quick and easy synthesis of benzaldehyde, heat phenylalanine with 5N NaOH solution for 5 hours, at 110 C,
it then decomposes, yielding benzaldehyde.

About as quick and easy as one can get, aspartame might be a good starting point for cheap as hell phenylalanine
Phenylalanine is an essential amino acid (a building block for proteins in t found he body), meaning the body needs it for health but cannot make it.
You have to get it from food. Phenylalanine is found in 3 forms: L-phenylalanine, the natural form found in proteins; D-phenylalanine
(a mirror image of L-phenylalanine that is made in a laboratory), and DL-phenylalanine, a combination of the 2 forms.

scientician - 24-2-2012 at 17:48

Carbon #8 on this badboy is the chiral one. If you oxidize it to the aldehyde, the chirality of the substrate won't matter. So don't worry about entantiomers.

Don't know what you're looking for in terms of a detailed synthesis. Just keep adding drain cleaner to water until it boils at 110 C, and that will be 5N. Then throw in however much phenylalanine you want. Then do an extraction thingy.

Or you could use like, toluene.

entropy51 - 24-2-2012 at 18:34

Quote: Originally posted by scientician  
Just keep adding drain cleaner to water until it boils at 110 C, and that will be 5N. Then throw in however much phenylalanine you want. Then do an extraction thingy.

Or you could use like, toluene.
Well this takes spoon feeding to a new low.

Try weighing the stuff on a balance, known to you infidels as "scales".

scientician - 24-2-2012 at 20:20

If you can't explain it simply, you don't understand it well enough.

Say what you will, but my section of undergrads tends to set the curve. :D

Of course, they always follow up with "but why?" I suspect cal will follow my direction to the letter.

Paddywhacker - 25-2-2012 at 01:33

Benzaldehyde in boiling 20% NaOH? What about Cannizzaro?

Nicodem - 26-2-2012 at 03:25

Quote: Originally posted by cal  
I have found many references to this but, Has anyone actually tried it and has a detailed synthesis.


If you want a quick and easy synthesis of benzaldehyde, heat phenylalanine with 5N NaOH solution for 5 hours, at 110 C,
it then decomposes, yielding benzaldehyde.

Such lazy posts are not really welcome here. It is expected you use at least the very minimum scientific attitude when opening threads. One such little step would be to actually UTFSE:
Quote: Originally posted by Nicodem  
I suspect benzaldehyde is not the product of such NaOH treatment of phenylalanine, but rather one of the products. Besides, this annoying claim was reposted already several times and none ever provided the reference, so it pretty much looks like some self reproducing misinformation.

5N NaOH and phenylalanine

cal - 24-3-2012 at 20:48

Quote: Originally posted by entropy51  
Quote: Originally posted by scientician  
Just keep adding drain cleaner to water until it boils at 110 C, and that will be 5N. Then throw in however much phenylalanine you want. Then do an extraction thingy.

Or you could use like, toluene.
Well this takes spoon feeding to a new low.

Try weighing the stuff on a balance, known to you infidels as "scales".

This reaction of phenylalanine and NaOH at 110C for 5 hours does not work.