13-Cyclopent-2-enyl-tridecanoate

Figure 5.1 Structures of naturally occurring cyclic fatty acids. I, Cyclopropane acids a, 9,10-methylenehexadecanoic acid b, 11,12-methyleneoctadecanoic (lactobacillic) acid c, 8,9-methy-leneheptadecanoic (dihydromalvalic) acid d, 9,10-methyleneoctadecanoic (dihydrosterculic) acid. II, Mycolic (2-alkyl-3-hydroxy) acid. Ill, Cyclopropene acids a, 9,10-methyleneoctadec-9-enoic (sterculic) acid b, 8,9-methyleneheptadec-8-enoic (malvalic) acid. IV, Cyclopentenyl acids a, ll-cyclopent-2-enyl-undecanoic (hydnocarpic) acid b, 13-cyclopent-2-enyl-tridecanoic (chaulmoogric) acid c, 13-cyclopent-2-enyl-tridec-6-enoic (gorlic) acid. V a, 11-cyclohexyl-undecanoic acid b, 11-cycloheptylundecanoic acid.

In this category, fatty acids with a terminal cyclopentenyl ring are best known (Sebedio and Grandgirard, 1989). There are three main types hydnocarpic (ll-cyclopent-2-enyl-undecanoic) acid (structure IVa, Fig. 5.1), chaulmoogric (13-cyclopent-2-enyl-tridecanoic) acid (structure IVb) and gorlic (13-cyclopent-2-enyl-tridec-6-enoic) acid (structure IVc) and its positional isomers (13-cyclopent-2-enyl-tridec-4-enoate and 13-cyclopent-2-enyl-tridec-9-enoate). They usually occur in varying proportions as major components (up to 90% of total fatty acids) in seed oils along with smaller amounts of saturated, oleic and linoleic acids. 

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