Sciencemadness Discussion Board

phenylalanine and carboxylic acid reduction

azoth - 2-4-2006 at 11:54

forgive me if this subject has already been discussed, but
i've searched the net and besides a general outline i can't find any specific information about how one would
completely reduce the acyl chloride of phenylalanine using sodium borohydride..

does anyone know any practical methods/links/tips on how much borohydride one would use on an acyl chloride? to reduce everything.

any information would be helpful.
thanks.

CherrieBaby - 2-4-2006 at 12:04

How would you prepare the acid chloride of phenylalanine? Wouldn't the acid Chloride react with the amino group internally? Perhaps the ester may be easier to reduce.

azoth - 2-4-2006 at 12:29

The information i've got says that thionyl chloride is used to make the acyl chloride from phenylalanine. what would it be called.
nomenclature is not my strong point
but 1-phenyl-(2-amino-3 propanioyl chloride) perhaps.?

since sod.borohydride isn't strong enough reducing agent to reduce the carboxylic acid directly, i was told that making the acyl chloride first was the best thing to do.

is sodium borohydride strong enough to competely reduce an ester like you mentioned?

runlabrun - 4-4-2006 at 05:20

close...
2-amino-3-phenylpropanoyl chloride

LiAlH4 is stronger however its going to take alot of excess agent (whatever you end up using) to go from COOH --> CH3 (as im assuming your looking at)... this means it will cost you a penny or 6...

-rlr

Madandcrazy - 6-4-2006 at 07:42

Is the pehnylalanin stable for this synthesis ?
When it threated with HCl, do it converted to
1-chloro-2-amino-propionic acid, to pehnylchloroethylamin or to pehnylacetylalanin ;) if it exist.
Maybe interested to this the DL-alanin within the -CH3NH2 group.

praseodym - 6-4-2006 at 17:43

By use of sodium borohydride in N,N-dimethylformamide solution containing a molar excess of pyridine as a borane scavenger, direct conversion of both aliphatic and aromatic acid chlorides to the corresponding aldehydes can be achieved in >70% yield with minimal (5-10%) alcohol formation.

Nicodem - 7-4-2006 at 03:30

2-amino-3-phenylpropanoyl chloride does not exists for obvious reasons. Its hydrochloride salt is probably the closest thing you can obtain.
Quote:
Originally posted by praseodym
By use of sodium borohydride in N,N-dimethylformamide solution containing a molar excess of pyridine as a borane scavenger, direct conversion of both aliphatic and aromatic acid chlorides to the corresponding aldehydes can be achieved in >70% yield with minimal (5-10%) alcohol formation.


Do you mind providing us the reference for such a reduction of acid chlorides to aldehydes.

solo - 7-4-2006 at 13:05

I've read the many ways to reduce the phenylalanine .......thus far one can make an ester and reduce to an alcohol, or use sodium borohydride and a metal (AlCl3) in water at RT to reduce to the phenylalaninol( the alcohol of phenylalanine) .........and by "all the way " do you mean to the hydrocarbon? For that you need to either halogenate and reduce or make the OH an easier leaving group to reduce , or dehydrate the alcohol but watch out for rearrangement , also one thing you should know ......the reduction to the hydrocarbon leads you to a restricted compound ....you should have a permit or be very careful............solo

praseodym - 7-4-2006 at 23:46

Quote:
Originally posted by Nicodem
Do you mind providing us the reference for such a reduction of acid chlorides to aldehydes.


No problem. Here is the link. This website talks about the reduction of acid chlorides to aldehydes using sodium borohydride and pyridine. Hope that it is useful :)