Syntheses of radioactive furan fatty acids

Abstract
A novel route for the synthesis of naturally occurring furan fatty acids with particular emphasis on labeling with14C is described. Methyl [2‐14C] 9‐(5‐pentyl‐3,4‐dimethyl‐2‐furyl)nonanoate was synthesized from 3,4‐dimethyl‐2‐pentylfuran by a new route. [3‐14C]11‐(5‐Pentyl‐3‐methyl‐2‐furyl)undecanoate and [2‐14C] 9‐(5‐pentyl‐2‐furyl)nonanoate were prepared from their lower homologs. The label was introduced in all cases by means of the Arndt‐Eistert method for chain elongation, using14CH2N2. Comparisons of yields show that, with increasing number of substituents on the ring, the furan compounds are increasingly subject to uncontrollable side reactions.