Carbon-13 NMR spectra of some 8,13-diazasteroids and related model isoquinolines

Carbon-13 NMR spectra of some dihydro- and tetrahydro-isoquinolines were studied and applied to the assignments of ¹³C NMR signals of some 8,13-diazasteroids related to the estrone series. Some deuterated compounds were also examined. All signals could be assigned and an important long-range isotopic effect was observed which seems to be due to an interaction between the C? H(D) bond and the nitrogen lone pairs.