The numbering system used for the 3-dehydroshikimic acid is that of the IUPAC/CBN recommendations on cyclitols, sections I-8 and I-9. The use of the term '5-dehydroshikimic acid' for this compound is based on an earlier, now obsolete, system of numbering (for example of use, see S. Mitsuhashi and B. D. Davis, Biochim. Biophys. Acta, 1954, 15, 268-280).