Sciencemadness Discussion Board

Dakin-West Reaction on Phenylalanine the Amino Acid

solo - 22-7-2005 at 12:43

I have a reaction that requires the removal of the CH3 from a ketone ,but first in a Dakin -West reaction the amino acid Phenylalanine is treated with acetic anhydride will make an ozaxolone, meaning a ketone where the carboxylic acid active group formerly resided and an amide where the amine group formerly resided. The task is to remove the CH3 to leave the alkane and the amide in place, later the amide can be reduced to a methylamine .

Here are some facts regarding Dakin-West reaction and how it can be applied to our Phenylalanine. "When an amino acid is treated with an anhydride in the presence of pyridine, the carboxyl group is replaced by an acyl group and the NH2 becomes acylated. This is called the Dakin-West reaction. The mechanism involves formationof an oxazolone. The reaction sometimes takes place on carboxyl acids even when an amino group is not present . A number of N-substituded amino acids , RCH(NHR' )COOH, give the corresponding N_alkylated products. " as stated on page 812 from 5th edition March's text.

Ref.
for a review, see Buchanan, G.L.Chem.Soc.Rev.,1988,17,91 Allinger, N.L.; Wang, G.L. ; Dewhyrst, B.B., Org. Chem., 1974,39,1730

Note:
...........pyridine can be substituded with sodium acetate or alkylpyradines,



Now here is an idea for removel of the CH3......March's 5th ed. page 318, .....through some photochemistry ketones can be processed through type I cleavage in the Norrish Type I cleavage



HV
R'-CO-R -------> R'-CO- + R

hence , need to find type of conditions and methods for this Norrish type I cleavage....any suggestions........solo

solo - 22-7-2005 at 19:16

Here is some info on the photochemistry reaction mentioned..........solo

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March's book.......see page 812 for reactionand ref.

solo - 12-8-2005 at 19:01

Well I'll do you one better her is a copy of the book for downloading............solo

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March's Advanced Organic Chemistry:Reactions Mechanisms and Structure 5th ed.
Michael B. Smith & Jerry March

http://rapidshare.de/files/965524/March_5th_ocr.rar.html

This is a searchable and a bit low resolution version of the one found by eMule (>200Mbyte).
Almost every reaction mentioned is referenced, as far as I can see.

I Hope you will find it useful!