A BICYCLIC KETONE AS A SOLID-STATE C-13 NMR INTENSITY REFERENCE

The synthesis and NMR relaxation properties of 4-(N-methylpyrrolidino)bicyclo[3.2.1]octan-8-one triflate (321) are described. The use of (CO)-C-13-enriched 321 as a C-13 intensity reference is justified and demonstrated. The dominant C-13 peak in 321-(CO)-C-13 is 217 ppm, far from most other C-13 chemical shifts of diamagnetlc organic compounds. Hence, this intensity reference peak avoids peak overlap problems for most organic compounds.