The synthesis of deuterium labeled macrocyclic polyethers (crown ethers)

Five tetradeuterated analogues ( 1a, 1b, 1c, 1d , and 1e ) of 3,6,9,12,15-pentaoxa-21-aza-bicyclo[15.3.1]heneicosa-1(21),17,19-triene (pyridyl-18-crown-6, 1 ) have been prepared corresponding to the five unique protonated carbon atoms of the polyether cycle. Deuterium labeling was ≥ 99% for four of the compounds and ≥ 97% for the other (1a ).