[1-C-14] N-methylneodecanamide (MNDA), a potent insect-repellent, was synth
esized from [1-C-12] neodecanoic acid (NDA) by an exchange variant of the K
och reaction, followed by conversion to the acyl halide and methylamination
. The product had all the characteristics of authentic commercial MNDA, and
the radiocarbon was distributed among the isomers in the same proportions
as the isomers were among the mass.