Talk:Barbituric acid

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Where are the "acid" hydrogens in this molecule? GCarty 15:55, 6 March 2006 (UTC)
 * The hydrogen atoms of the methylene (the -CH2- between the two carbonyl groups) are mildly acidic - much like Meldrum's acid. Edgar181 16:05, 6 March 2006 (UTC)

About the structure...
Sorry if I sound ignorant but I thought the C5 in the Barbituric acid diagram had two H's coming off it. How come the diagram in the article doesn't show the two H atoms?
 * chemists are lazy people and in generally will not draw the hydrogen atoms, they are implied V8rik 22:13, 18 November 2006 (UTC)

Resonance of Deprotonated BA
The picture of the deprotonated barbituric acid is incorrect for the following reasons:

1. The most acidic proton in the trioxo form are the ones on the N, a lactim is formed (dioxo form).

2. The final "resonance structure" is not a resonance structure, but a "hybrid", Furthermore, it is an incorrect hybrid.

Barbaturic acid tautomerizes. Experimental studies show that salt formation takes place from the dioxo form.

See Burger's Medicinal Chemistry. I have 4th Ed., vol III, p 795.

I would be happy to help with a corrected version. Hokietiki@hotmail.com (talk) 18:27, 18 February 2011 (UTC)
 * Your concerns seem valid to me, so I have removed the image. I'll work on creating a new one a little later today.  -- Ed (Edgar181) 17:59, 23 February 2011 (UTC)
 * Looking into this a little closer, I can't find anything that definitively says which proton is the most acidic, and I don't have access to Burger's Medicinal Chemistry. However, reactions such as alkylation under basic conditions give products of reaction at the methylene, which suggests that position is the most acidic.  I agree with you though, that the final "resonance structure" in the image is not resonance, but rather a mix of tautomers.  -- Ed (Edgar181) 18:51, 23 February 2011 (UTC)

Assessment comment
Substituted at 08:58, 29 April 2016 (UTC)

Date of discovery: 1864 ?
At present (6 October 2016), this article states: "The compound was discovered by the German chemist Adolf von Baeyer on December 4, 1864, the feast of Saint Barbara (who gave the compound its namesake) … "

However, Baeyer clearly discovered and named barbituric acid in 1863:

Baeyer, Adolf (1863) "Untersuchungen über die Harnsäuregruppe" (Investigations of the uric acid group), Annalen der Chemie, 127 : 199–236 ; see pp. 231–235.

On page 233, you can clearly read "Barbitursäure" (barbituric acid).

So, if no one objects, I'll replace the original text with: "The compound was discovered by the German chemist Adolf von Baeyer in 1863 … "

VexorAbVikipædia (talk) 08:27, 6 October 2016 (UTC)