Penta-2,3-dienedioic acid (one of two chemicals called glutinic acid), is in
allene
In organic chemistry, allenes are organic compounds in which one carbon atom has double bonds with each of its two adjacent carbon centres (). Allenes are classified as diene#Classes, cumulated dienes. The parent compound of this class is propa ...
-containing
dicarboxylic acid
In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids show ...
. It was the first allene to be synthesized, in 1887, but the structure of it was thought to be a
propyne
Propyne (methylacetylene) is an alkyne with the chemical formula . It is a component of MAPD gas—along with its isomer propadiene (allene), which was commonly used in gas welding. Unlike acetylene, propyne can be safely condensed.Peter Päs ...
core instead of an allene. The correct
structural isomer
In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a chemical compound, compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct chemical bond, b ...
ic identity was not determined until 1954.
Literature confusion
A diterpene, chemical name (4a''R'',5''S'',6''R'',8a''R'')-5-
''Z'')-4-carboxy-3-methylbut-3-enyl5,6,8a-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
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...
rather than the allene meaning in the underlying publications.
[See patents listed for ]
References
{{organic-compound-stub
Enoic acids
Dicarboxylic acids