|   | |
| Names | |
|---|---|
| Preferred IUPAC name (2E,4E)-5-(2H-1,3-Benzodioxol-5-yl)penta-2,4-dienoic acid | |
| Identifiers | |
| 3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| EC Number | 
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| MeSH | C017637 | 
|  PubChem CID | |
| UNII | |
|  CompTox Dashboard (EPA) | |
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| Properties | |
| C12H10O4 | |
| Molar mass | 218.208 g·mol−1 | 
| Boiling point | decomposes | 
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Piperic acid is a chemical often obtained by the base-hydrolysis of the alkaloid piperine [1] from black pepper, [2] followed by acidification of the corresponding salt. Piperic acid is an intermediate in the synthesis of other compounds such as piperonal, and as-such may be used to produce fragrances, perfumes flavorants and drugs as well as other useful compounds.
Piperic acid can be prepared from the commercially available alkaloid piperine, a cyclic amide containing a piperidine group, by reacting it with a hydroxide such as potassium hydroxide, then acidifying the formed piperate salt with hydrochloric acid or another acid. The toxic compound piperidine is given off during the base-hydrolysis of piperine and as-such, safety precautions should be taken.
 
 Reaction of piperic acid with strong oxidizers such as potassium permanganate or ozone, or a halogen such as bromine followed by sodium hydroxide causes oxidative cleavage of the double-bonds, yielding piperonal and piperonylic acid. [3] Piperonal has many uses in industry and is itself a precursor to a good subsection of other chemicals. On reduction with sodium amalgam piperic acid forms α- and β-dihydropiperic acid, C12H12O4, and the latter can take up two further atoms of hydrogen to produce tetrahydropiperic acid.