Abstract 13 C NMR spectra of compounds related to aristolochic acid and aristololactam, the constituents of Aristolochia indica, have been studied to determine the chemical shifts and coupling constants of polysubstituted phenanthrenes. Selective 1 H decoupling and long- range couplings were utilized for the assignments. Substituent-induced chemical shifts and also the effects on coupling constants could be deduced in some cases. Anion formation ...