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Meldrum's acid

Meldrum's Acid

IUPAC name	2,2-Dimethyl-1,3-dioxane-4,6-dione
Identifiers
CAS number	2033-24-1
SMILES	O=C(C1)OC(C)(C)OC1=O
Properties
Molecular formula	C₆H₈O₄
Molar mass	144.1253 g/mol
Density	? g/cm³
Melting point	94-96 °C
Boiling point	°C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Meldrum's acid or 2,2-dimethyl-1,3-dioxane-4,6-dione is an organic compound. The main ring structure is a dioxane. The compound was discovered in 1908 by A.N. Meldrum^[1] and it is prepared by a condensation reaction of malonic acid with acetone in acetic anhydride with sulfuric acid. Meldrum misidentified^[2] the structure as a beta-lactone with a fully fledged carboxylic acid group. Yet Meldrum's acid has a high acidity with a pKa of 4.97, because like ascorbic acid, deprotonation at the methylene next to the carbonyls produces a stable enolate. Because of this property Meldrum's acid like malonic acid is a reactant in Knoevenagel condensations.

References

^ Meldrum, A. N. J. Chem. Soc. 1908, 93, 598.
^ The Structure of Meldrum's Supposed beta-Lactonic Acid David Davidson, Sidney A. Bernhard; J. Am. Chem. Soc.; 1948; 70(10); 3426-3428. doi:10.1021/ja01190a060