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, Et, Pr, hexyl) or phenylselenide with methyl 10, 11- epoxyundecanoate gave the corresponding ethyl 10-hydroxy-11-alkyl (phenyl) seleno- undecanoates. The 1H-NMR spectroscopic analysis revealed strong hydrogen-bonding ...