Saturated keto esters from lesquerolic,dimorphecolic, and densipolic acids

Summary The naturally occurring, unsaturated, hydroxy fatty esters, methyl lesquerolate (methyl 14-hydroxy-cis-11-eicosenoate), methyl dimorphecolate (methyl 9-hydroxy-trans, trans-10,12-octadecadienoate), and methyl densipolate (methyl 12-hydroxy-cis,cis-9,15-octadecadienoate) have been converted to the corresponding saturated keto esters by tow routes. The unsaturated esters were subjected to a hydrogenation-dehydrogenation reaction in the presence of Raney nickel or their saturated derivatives were dehydrogenated by copper chromite catalysis. Yields of the keto esters are 65–82% in the nickel-catalyzed reactions, and 71–94% by copper chromite-catalyzed dehydrogenation. In the hydrogenation-dehydrogenation system the order of reactivity is: methyl lesquerolate>methyl dimorphecolate>methyl densipolate. Relationships between structure and reactivity of these compounds, methyl 12-hydroxystearate, and methyl ricinoleate are discussed. W. Utiliz. Res. Dev. Div., ARS, USDA.