Ma. Tetrick et al., SYNTHESIS OF [9-C-14]NONANOIC ACID VIA 2-THIENYL((CH3)-C-14)(CYANO)CUPRATE AND ITS OXIDATION BY NEWBORN PIGLET MUSCLE STRIPS, Analytical biochemistry, 248(1), 1997, pp. 1-6
To determine if newborn piglet muscle could oxidize propionyl-CoA form
ed by catabolism of odd chain fatty acids, an odd chain fatty acid lab
eled in the terminal three carbons was needed. The synthetic scheme de
scribed is based upon the displacement of a primary alkyl iodide, ethy
l 8-iodooctanoate, by a [C-14]methyl group via an activated 2-thienyl(
(CH3)-C-14) (cyano)cuprate intermediate, forming ethyl [9-C-14]nonanoa
te. Ethyl [9-C-14]nonanoate was hydrolyzed in 6 N KOH and [9-C-14]nona
noic acid recovered by ion-exchange chromatography. The yield of [9-C-
14]nonanoic acid was 40%, based on the initial amount of [C-14]methyl
iodide. The cuprate and other precursors mere commercially available o
r readily synthesized from available precursors. Mass spectroscopy of
commercial and synthesized nonradioactive nonanoate determined an m/z
of 159 for the product molecular ion, as expected. The C-14-labeled pr
oduct phenacyl ester was found to cochromatograph in a C-18 reverse-ph
ase HPLC system with similarly derivatized commercially obtained nonan
oic acid. The synthesis should be generally applicable to labeling of
compounds by displacement of primary alkyl iodides, where other reacti
ve groups (e.g., carboxylic acid),if present, can be protected (e.g.,
converted to an ester). Muscle strips isolated from the triceps muscle
of newborn piglets oxidized [9-C-14]nonanoic acid to (CO2)-C-14. Newb
orn piglet muscle can oxidize propionyl-CoA produced during odd-chain
fatty acid oxidation. (C) 1997 Academic Press.