SYNTHESIS OF KETODIENOIC AND HYDROXYDIENOIC COMPOUNDS FROM LINOLEIC-ACID

A convenient preparative method has been developed for the synthesis o f hydroxydienoic (8-HODE and 13-HODE) and ketodienoic compounds (9-KOD E and 13-KODE) from natural linoleic acid. Methyl linoleate was treate d with 1.25 eq. of m-chloroperbenzoic acid in alcoholic solution, givi ng a mixture of mono-epoxides (yield 60%), that was treated with a sol ution of HBr in MeOH to yield a mixture of the bromohydrins (yield 92% ). The last was oxidized by Jones reagent to a mixture of bromoketones (yield 64%) and the mixture obtained was dehydrobrominated by DBU to produce a mixture of ketodienoic compounds (yield 94%). Reduction of t he ketodienoic compounds by KBH4 in MeOH led to the corresponding hydr oxydienoic (9-HODE and 13-HODE) methyl esters (yield 83%). The synthet ic approach described is simple and gives reliable results. The keto- and hydroxy fatty acids obtained were characterized thoroughly by TLC, HPLC, UV, FT-IR, H-1-, (HH)-H-1-H-1- and C-13-NMR. (C) 1997 Elsevier Science Ireland Ltd.