Piperonal

Piperonal (heliotropine, protocatechuic aldehyde methylene ether) is an aromatic aldehyde that comes as transparent crystals, C8H6O3, and has a floral odor. It is used as flavoring and in perfume. It can be obtained by oxidation of piperonyl alcohol. It is also a minor natural component of the extract of vanilla.

It may be used in the synthesis of 3,4-methylenedioxyamphetamine (MDA). In one synthetic path, nitroethane in a glacial acetic acid solution with an ammonium acetate catalyst yields a substituted nitrostyrene via a condensation reaction. This intermediate can then be reduced in the presence of a strong reducing agent such as lithium aluminum hydride (LiAlH4) to yield MDA.