SYNTHESIS OF (9Z,12E)-,(9E,12Z)-[1-C-14]-LINOLEIC ACID, (92,12Z,15E)-,(9E,12Z,15Z)-[1-C-14]-LINOLENIC ACID AND (5Z,8Z,11Z,14E)-[1-C-14]-ARACHIDONIC ACID

Trans polyunsaturated fatty acids are produced in vegetable oils durin g heat treatment (240-250 degrees C). In order to study the metabolic pathway of 9c,12t and 9t,12c linoleic acid and 9c,12c,15t and 9t,12c,1 5c linolenic acid, these products were prepared labelled with carbon 1 4 in the carboxylic position. 5c,8c,11c,14t-Arachidonic acid was also labelled on the carboxylic position with carbon 14 in order to study i ts physiological effects. To introduce the labelling (E)-bromo precurs ors with a 17 carbons chain or a 19 carbon chain were needed. The diff erent syntheses were done by elongation steps and creation of cis doub le bonds via highly stereospecific Wittig reactions. The radioactive c arbon atom was introduced from [C-14]-potassium cyanide. The final rad ioactive fatty acids had a specific activity greater than 50 mCi/mmol and a radioactive purity better than 99 % for linoleic and linolenic a nd better than 98.6 % for arachidonic acid.