stoichiometric_steve - 29-9-2007 at 08:02
in Synth.Comm., 32(3), 457-465 (2002), a nice method for n-methylation of amines is given. i posted the ref in solos "methylation problems" thread.
the authors use paraformaldehyde and oxalic acid dihydrate at 100°C as methylation and reduction agent. if this method would also fit for amino
acids, which are commonly methylated by Schiff base formation with benzaldehyde and subsequent methylation with nasty (nasty!!) dimethyl sulfate, the
latter could be avoided.
moreover, does anybody know if alpha-ketocarboxylic acids can be reductively aminated with aliphatic amines as in standard procedures for ketones, or
are there any problems that need to be solved?
[Edited on 29-9-2007 by stoichiometric_steve]
solo - 29-9-2007 at 15:55
This recent post may be of interest to you posted in articles of interest in the reference section......solo
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Reductive methylation of primary and secondary amines and amino acids by aqueous formaldehyde and zinc
Renato A. da Silva, Idalia H. S. Estevam and Lothar W. Bieber
Tetrahedron Letters 48 (2007), 7680-7682
Abstract
Amines can be methylated when treated with formaldehyde and zinc in aqueous medium. Selective mono- or dimethylation can be achieved by proper choice
of pH, stoichiometry and reaction time. This method can also be applied for amino acids.
https://sciencemadness.org/talk/viewthread.php?tid=5805&...
[Edited on 30-9-2007 by solo]
stoichiometric_steve - 30-9-2007 at 07:31
wow, solo! Thanks alot.
now, is there a separation method (besides electrophoresis) which is applicable to multigram batches of amino acids?
Eclectic - 30-9-2007 at 12:30
Liquid-solid chromatography. Ion exchange chromatography.
Google "amino-acid separation"
[Edited on 9-30-2007 by Eclectic]