Truly?
Seems I was wrong then - of course you won't mind providing poor lil' ol' me with the specific, detailed reaction that occurs when alkylating an amino
acid via the akabori procedure? I'd really like to read it, 'cos though I've seen it cited many, many, many times, I have yet to see anybody detail
anything which provides a detailed overview of how the reaction works - unless it is analoguous to these reactions:
You'll probably have noted that the alkylation only proceeds once the imine is formed from the amino acid and the second equivalent of the aldehyde?
That is what I was suggesting, although I don't know how well it would work with formaldehdye - what about forming the imide with formic acid?
See for instance this article - where the author's prepared phenylserine by reference to the method of Akabori:
http://www.jbc.org/cgi/reprint/237/10/3229.pdf
Whereas this paper deals with the preparation of phenylserine via the known method (but does not mention Akabori)
http://studentsupport.syr.edu/upload/Tracey-Ann%20Samuels%20...
Now as the other name for phenylserine is b-hydroxyphenylalanine and it is formed by the alkylation of the n-benzylidene-glycine with another
equivalent of benzaldehyde, it makes sense that if one used alanine (which by analogy seems to have been the method of Akabori) that one would get
a-methyl-b-hydroxy-phenylalanine which upon decarboxylation (heat will do it apparently) gives PPA.
Now if you look about, the alkylation of n-benzylidene-glycine/alanine with benzyl halides gives the appropriate a-alkylated phenylalanine (glycine
gives phenylalanine & alanine gives a-methylphenylalanine) both still require the formation of the imine by reaction of a substituent on the amine
group of the amino acid - which effectively removes it from further reaction.
[Edited on 14-5-2008 by LSD25]
Whhhoooppps, that sure didn't work
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