SYNTHESIS AND PHYSICAL-PROPERTIES OF SOME UNSATURATED AND HYDROXY ALKYLSELENO FATTY-ACID DERIVATIVES

Three unsaturated 12-alkylseleno (alkyl=Me, Et, Pr) C18 derivatives were prepared by reaction of sodium alkylselenide with the tosyloxy derivative of methyl ricinoleate. Reaction of sodium alkylselenide (alkyl = Me, Pt, Pr, hexyl) or phenylselenide with methyl 10,11-epoxyundecanoate gave the corresponding ethyl 10-hydroxy-11-alkyl(phenyl)seleno-undecanoates. The H-1-NMR spectroscopic analysis revealed strong hydrogen-bonding between the selenium atom and the hydroxy function. Acid-catalyzed dehydration of methyl 10-hydroxy-11-methylseleno-undecanoate gave methyl 10-undecenoate as the major product, due to neighboring participation reaction of the selenium atom in the alkyl chain. To demonstrate the stability of unsaturated selenium-containing fatty acid analogues, the total synthesis of methyl 11-methyl-seleno-9-cis-undecenoate was elaborated.