Talk:MPTP

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Contents 1 Structural Drawing vs IPUAC Name 2 Rats 3 Apes? 4 Langston's patients

[edit] Structural Drawing vs IPUAC Name

Dear Madams and Sirs:

Your article on MPTP states that the IUPAC name for that substance is 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Would you please check to see whether that stated name is correct?

According to the stated name, nitrogen occupies the "1" position in the heterocyclic ring, since the nitrogen in the structural formula is the atom to which the methyl group is bound. However, while the structural formula shows no hydrogen bound to that nitrogen, the stated name indicates that a hydrogen is bound to that nitrogen. It is hard to see how the stated name and the structural formula can both be correct.
Sincerely yours,

James W. Frederiksen, MD
Northwestern University Feinberg School of Medicine
Chicago, IL 60611
[excessive personal info removed -- DMacks]

To learn more about the Bluhm Cardiovascular Institute, please visit our web site at http://www.nmff.org/clinicaldepts/department.asp?id=66!"
—The preceding unsigned comment was added by James W. Frederiksen (talk • contribs) 14:38, 31 May 2006 (UTC)

The IUPAC web site verifies the name, so the graphic must be wrong. I have found some images of MPTP on Google image search that match my graphic…

• http://www.neurosci.pharm.utoledo.edu/MBC3320/dopamine.htm
• http://www.chemsoc.org/chembytes/ezine/1997/stachuls.htm
• http://holivo.pharmacy.uiowa.edu/morphine/chsix/mptp.html

…and some that don't.

• http://pharma1.med.osaka-u.ac.jp/textbook/Antiparkinsonian/Antiparkinsonian.html
• http://www.parkinson-web.de/popup/ursach_mptp1.html
• http://connection.lww.com/products/foye/quizch20.asp

Can anyone familiar with chemistry figure this out?

Foobaz·o< 01:49, 19 September 2006 (UTC)

If the image is correct, I think the name should be 1-methyl 4-phenyl 2,3,6-trihydropyridine. If the name is correct, the structure should have a hydrogen on the nitrogen atom, as Dr. Frederiksen describes. So now we just have to find which is correct.

This page: [1] shows MPTP as it is in the article's image, and has a reference to Chem.Eng.News 1981, 71, which I don't have access to. If someone who does have access could look at that, it might be helpful. Gary 03:10, 19 September 2006 (UTC)

The Aldrich catalog gives the name as "1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine" and the image as drawn in the article (double bond in conjugation with the phenyl).[2]. "Hydro" doesn't literally mean "an extra hydrogen atom is present", just that there is not an expected double bond present. Consider the parent pyridine structure, with double bonds between N (position 1, using the given numbering) and C2, between C3 and C4, and between C5 and C6. If you undo the double bonds on positions 1,2,3,6, you get the image as given. Adding three hydrogens wouldn't even give a stable structure, since you would not have acquired the lone-pair on N. OTOH, even if we take the name as a literal instruction to hydrogenate the N1-C2 and C3-C6 double bonds, you get the same structure as drawn except with the N protonated (for example, the known MPTP•HCl salt). So the image as drawn is just the conjugate base of that salt. Foobaz: I disagree with your image-search results—the osaka-u and the lww sites both have the image as drawn in the wikipedia. DMacks 05:29, 19 September 2006 (UTC)

See Wikipedia:Reference_desk/Science#MPTP_article_image for more discussion on the image's correctness. Foobaz·o< 01:54, 20 September 2006 (UTC)

I believe DMacks is correct. Here [3] is the IUPAC guide for naming these, although this specific case isn't covered, where the double bond is removed a methyl group (instead of another hydrogen) is attached to the nitrogen. It does say that "hydro" is added in pairs, so "trihydropyridine" is probably out. The images and descriptions found can't be all wrong, can they? Bennybp 03:20, 20 September 2006 (UTC)

[edit] Rats

The neurotoxicity of MPTP was discovered in 1976 after Barry Kidston, a 23-year-old chemistry graduate student in Maryland, synthesized MPPP incorrectly and injected the result. It was contaminated with MPTP, and within three days he began exhibiting symptoms of Parkinson's disease. The National Institute of Mental Health found traces of MPTP in his lab and eventually discovered its effects by testing the chemical on rats."

According to my university lectures, rats are immune to the neurotoxic effects of MPTP. This means its is unlikely these effects were confirmed by testing on rats as stated in the article.

[edit] Apes?

Are you sure it was initally tested on apes? The article later says it was first tested in squirrel monkeys (which aren't apes).

[edit] Langston's patients

Didn't Langston have six patients, not seven as stated? They were Connie, George, Juanita, David, Bill and Toby. If there is a seventh patient who was it? —The preceding unsigned comment was added by 134.153.182.147 (talk • contribs) 18:08, 26 February 2007 (UTC)

This article reads a bit Langston-centric. Richard8081 20:39, 12 September 2007 (UTC)