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Syntheses of geometric isomers of di‐, tetra‐, and hexadeuterated 12‐octadecenoates and their triglycerides
Author(s) -
Rakoff Henry,
Emken Edward A.
Publication year - 1978
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580150130
Subject(s) - chemistry , wittig reaction , triphenylphosphine , methyl iodide , bromide , iodide , phosphonium , phosphonium salt , medicinal chemistry , cis–trans isomerism , aldehyde , thermal decomposition , tetra , organic chemistry , catalysis
Four geometrically isomeric deuterated 12‐octadecenoates and their triglycerides were synthesized for use in metabolism studies in humans. Methyl trans ‐12‐octadecenoate‐15,15,16,16‐d 4 (81.7% d 4 ) and the corresponding cis isomer (88.9% d 4 ) were obtained by the Wittig reaction between hexyl‐3,3,4,4‐d 4 ‐triphenylphosphonium bromide (or iodide) and methyl 12‐oxododecanoate. The phosphonium salt was derived, in several steps, from 3‐hexynol and the methyl 12‐oxododecanoate from cyclododecene. Methyl cis ‐12‐octadecenoate‐9,10,15,15,16,16‐d 6 (79.9% d 6 ) was obtained via the Wittig reaction between hexyl‐d 4 ‐triphenylphosphonium bromide and methyl 12‐oxododecanoate‐9,10‐d 2 . This deuterated aldehyde ester was prepared by lead tetraacetate oxidation of methyl 12,13‐dihydroxyoctadecanoate‐9,10‐d 2 which was obtained, in several steps, from Vernonia anthelmintica seed oil. A simple and convenient stereospecific synthesis of methyl trans ‐12‐octadecenoate‐9,10‐d 2 (84.9% d 2 ) was accomplished by thermal decomposition of methyl 12,13‐di‐O‐(ethoxymethylene)‐octadecanoate‐9,10‐d 2 which was prepared, in several steps, from 12,13‐epoxy‐9‐octadecenoate obtained from Vernonia oil. All deuterations were catalyzed by tris(triphenylphosphine)chlororhodium. cis ‐ and trans ‐ isomers were separated on an Amberlyst XN 1005 column impregnated with silver ions.