Assignment of the carbon-13 chemical shifts of quinacrine,chloroquine and related compounds in D2O solution

The carbon resonances of quinacrine, chloroquine, acranil, 4-aminopyridine and 9-aminoacridine in D₂O solution have been assigned. Resonance assignments were made using empirical shift parameters, partial proton decoupling, selective proton decoupling and by interpretation of the fully coupled spectra. The effect of pD on the carbon chemical shifts for quinacrine and chloroquine over the range of about 4.5 to 8.5 was observed. Characteristic chemical shifts for the aromatic ring carbons for deprotonation of the heteroaromatic nitrogen were observed.