Synthesis of (~(13)C5) and (carbonyl-~(14)C)-5-chlorofuran-2-carboxylic acid

摘要

The inventory of labeled compounds and methods for their preparation are constantly growing, but still more building blocks of biologically relevant compounds need to be developed. Furans are frequently encountered in bioactive molecules, and a good synthesis of labeled furan is found in the literature. We required a relatively uncommon labeled furan, 5-chloro-2-furoic acid, for investigative work labeled with C-13 and C-14. Carboxylation of the lithium anion of [~(13)C_4]furan with ~(13)CO_2 followed by chlorination using benzyltrimethylammonium dichloroiodate provided the target compound in modest yield and high purity. The same procedure was then repeated with unlabeled furan and ~(14)CO_2 to give [carbonyl-~(14)C]-5-chlorofuran-2-carboxylic acid.