The synthesis of 14C, 3H and 2H labeled 7‐ethoxycoumarins

Abstract
7‐Ethoxycoumarins labeled in the ethoxy side chain were prepared from 7‐hydroxycoumarin and the correspondingly labeled ethyl iodide or ethyl tosylate. Persulfate oxidation of 7‐[1,1‐2H2]ethoxycoumarin gave 7‐[1,1‐2H2]ethoxy‐6‐hydroxycoumarin. 7‐[1,1‐2H2]‐Ethoxy[6‐2H]coumarin was prepared from 7‐hydroxy[6‐2H]coumarin, obtained via NaB2H4/PdCl2 reduction of 6‐chloro‐7‐hydroxycoumarin.