Sciencemadness Discussion Board

Paraxanthine

Ragnarok - 30-7-2008 at 09:22

I searched the forum and found nothing relevant, searched google and found only med journals, so any help from you guys would be most apreciated :)

Here goes: I need the metabolites of caffeine, paraxanthine in particular. All I found is that some enzyme in the liver breaks up caffeine into the methyl-xanthines, with a preference for paraxanthine (84%... yay!).
Is there any chemical way to do the same thing (get rid of a methyl group attached to a nitrogen) but not more (as in don't go all the way to xanthine). An alternative would be to go all the way to xanthine and re-methylate selectively, but i somehow suppose that's harder.
The small five membered ring of xanthine looks aromatic to me, so the N-me bound might be stronger (that could explain why it is the least likely to break).
Please help! I don't want to put fresh pig liver through my blender and use it as a catalyst :o

Ritter - 30-7-2008 at 09:36

You should check out these papers:

Mueller, CE et al Synthesis 1998 (10), 1428-1436. It gives a synthesis of paraxanthine.

Schmidt P Helv Chim Acta 1958, 1052-1060. Same comment.

[Edited on 30-7-2008 by Ritter]

[Edited on 30-7-2008 by Ritter]

Ragnarok - 30-7-2008 at 09:41

I should. But I can't. I don't have a subscription to anything and can't afford one. Our school had free access to sciencedirect, but that's gone too. And a library that has journals newer than the 80's would be impossible to find in my country :(
Thanks, anyway!

[Edited on 30-7-2008 by Ragnarok]

ScienceSquirrel - 30-7-2008 at 09:55

This journal looks like it might have a synthesis;

http://www.springerlink.com/content/w5h1273202263125/

solo - 30-7-2008 at 12:17

Quote:
Originally posted by Ritter
You should check out these papers:

Mueller, CE et al Synthesis 1998 (10), 1428-1436. It gives a synthesis of paraxanthine.

Schmidt P Helv Chim Acta 1958, 1052-1060. Same comment.

[Edited on 30-7-2008 by Ritter]

[Edited on 30-7-2008 by Ritter]


See the madhatters ftp as many of the synthesis volumes reside there......solo

here is the other reference......
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Heilmittelchemische Studien in der heterocyclischen Reihe. 22. Mitteilung. Pyrazolo-pyrimidine II. Pyrazolo[3,4-d]pyrimidine mit Koffein-ähnlicher Struktur und Wirkung
P. Schmidt, K. Eichenberger, J. Druey
Helvetica Chimica Acta Volume 41, Issue 4,(p 1052-1060), 1958

Attachment: Heilmittelchemische Studien in der heterocyclischen Reihe. 22. Mitteilung. Pyrazolo-pyrimidine II. Pyrazolo[3,4-d]pyrimi (1.1MB)
This file has been downloaded 608 times

Ragnarok - 31-7-2008 at 10:54

Thanks guys!
One more thing though... what on god's green earth is the madhatters ftp?
Solo, thanks a lot for the text, i'll try to get someone to translate for me :) If I find out how to make this, i'll let you all know.

solo - 31-7-2008 at 15:07

Synthesis of Paraxanthine and Isoparaxanthine Analogs (1,7- and 1,9-Substituted Xanthine Derivatives)
Christa E. Müller, Dirk Deters, Andreas Dominik, Maciej Pawlowski
Synthesis pg.1428, 1998


Abstract:
A general, convenient method for the preparation of
1,7- and 1,9-disubstituted xanthine derivatives (paraxanthine and
isoparaxanthine analogs) was developed starting from 6-amino-2-
methoxypyrimidin-4-one. Alkylation with alkyl halides in acetone/potassium carbonate in the presence of a phase-transfer catalyst
(PTC) yielded an equimolar mixture of N3- and O 4 -alkylatedproducts, which could be separated by dry column chromatography.
The N3-alkylated uracil derivatives were converted to the
corresponding 1-alkyl-2-methoxypurin-6-ones by standard procedures.
PTC alkylation yielded an equimolar mixture of 7- and 9-
alkylated isomers, which were again conveniently separated by
dry column chromatography. The title compounds were obtained
after acid hydrolysis of the 2-methoxy group in satisfactory
yields.

Key words:
paraxanthine, isoparaxanthine, xanthine synthesis,
alkylation, phase transfer catalysis

Attachment: synthesis page 1428, 1998.pdf (71kB)
This file has been downloaded 3991 times