Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2001
Publication Date: N/A
Technical Abstract: Long chain fatty esters containing heterocyclic structures in the alkyl chain are of increasing interest from both industrial and biological perspectives. The delta 2-isoxazoline ring structure can be obtained from the 1,3-dipolar cycloaddition reaction between an olefinic substrate and reactive nitrile oxides that are generated in situ by reacting aldoximes with aqueous sodium hypochlorite and a catalytic amount of triethylamine. Fatty ester delta 2-isoxazoline heterocycles were prepared in good yields and excellent regioselectivity from the 1,3-dipolar cycloaddition reactions between methyl 10-undecenoate and various nitrile oxides. Olefinic substrates based on natural fatty esters, such as methyl oleate and methyl elaidate, were also reacted with nitrile oxides to give regioisomeric mixtures of their corresponding delta 2-isoxazoline heterocycles in low to moderate yields. Because delta 2-isoxazolines are versatile synthetic intermediates, transformations of these fatty ester heterocycles were also examined. Raney nickel mediated hydrogenolysis/hydrolysis of the isoxazoline ring gave good yields of fatty ester compounds containing a beta-hydroxy ketone moiety in the alkyl chain. These compounds may have potentially interesting chemical and physical properties and are not easily accessible by other methods.