Penta-2,3-dienedioic acid


Penta-2,3-dienedioic acid, is an allene-containing dicarboxylic acid. It was the first allene to be synthesized, in 1887, but the structure of it was thought to be a propyne core instead of an allene. The correct structural isomeric identity was not determined until 1954.
Glutinic acid, a substituted allene, was isolated from Alnus glutinosa.

Literature confusion

A diterpene, chemical name -5--5,6,8a-trimethyl-3,4,4a,6,7,8-hexahydronaphthalene-1-carboxylic acid, is also called glutinic acid. Some database entries for "glutinic acid" incorrectly identify it as this diterpene rather than the allene meaning in the underlying publications.