1,3-Indandione
Chemical compound
From Wikipedia, the free encyclopedia
1,3-Indandione (sometimes simply indanedione) is an organic compound with the molecular formula C6H4(CO)2CH2. It is a β-diketone with indane as its structural nucleus. It is a colorless or white solid, but old samples can appear yellowish[3] or even green. It is a popular chemical scaffold (building block of various useful chemical compounds),[4][5] and derivatives antagonize Vitamin K receptors.[6]
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| Names | |
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| Preferred IUPAC name
1H-Indene-1,3(2H)-dione | |
| Other names
Indandione; 1,3-Diketohydrindene; 1,3-Dioxoindane; 1,3-Hydrindendione | |
| Identifiers | |
3D model (JSmol) |
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.009.191 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C9H6O2 | |
| Molar mass | 146.145 g·molâ1 |
| Appearance | white solid |
| Density | 1.37 g/cm3 |
| Melting point | 129 to 132 °C (264 to 270 °F; 402 to 405 K)[1][2] |
| slight | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structural properties
Solid 1,3-indandione is a diketone, As a solution in water, it is partially (~2%) enolized. The enolate anion exhibits significant delocalization, and the highest electron density is on the second carbon. This acid-base behavior explains many properties of the compound.[citation needed]
Preparation
1,3-Indandione was first obtained by Claisen condensation of ethyl acetate and dimethyl phthalate.[7] A related route entails the reaction of benzoyl chloride with malonyl dichloride.[8] It also can be obtained by oxidation of indane.
Chemical properties
The structure of the title compound has been confirmed by X-ray crystallography.[9] Unlike some other 1,3-diketones, it does not crystallize as the enol.
The carbon at the C-2 position is alpha to both carbonyls, and thus can act as a nucleophile. It undergoes self-aldol condensation easily, resulting in bi- and triindone.
Bromination occurs at the 2-position:
- C6H4(CO)2CH2 + 2 Br2 â C6H4(CO)2CBr2 + 2HBr
One or both carbonyl groups can be reduced to alcohol groups or methylene groups, depending on the method used.
- C6H4(CO)2CH2 + H2 â C6H4(CHOH)(CO)CH2
- C6H4(CO)(CHOH)CH2 + H2 â C6H4(CHOH)2CH2
- C6H4(CO)2CH2 + 4 H2 â C6H4(CH2)2CH2 + 2 H2O
Uses
1,3-Indandiones with a substituent at the 2-position are potent rodenticides. Commercial products include pindone, chlorophacinone, and diphenadione. These compounds function as vitamin K antagonists, inducing hemorrhage in the affected animals.[10]
