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.

Preparation

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.

Piperic acid from piperine

Reactions

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.

See also

References

  1. ^ Paul M. Dewick. (2009). Medicinal natural products : a biosynthetic approach. Chichester: A John Wiley & Sons. p. 327. ISBN 978-0-470-74167-2.
  2. ^ E. Gildemeister. The Volatile Oils. Vol. 1.
  3. ^ US 5095128, "Preparation process for piperonal"