Carbon-13 and proton NMR studies of 1,4-benzodiazepines

One bond and long range ¹H-¹H, ¹H-¹⁹F, ¹³C-¹H and ¹³C-¹⁹F coupling constants for six 1,4-benzodiazepines are described. An unambiguous assignment of their carbon-13 resonances is carried out based on chemical shift theory and on the analysis of the fine splittings caused by one bond and long range couplings. Chemical shift and coupling constant values are reported for diazepam, chlordiazepoxide, oxazepam, nitrazepam, chlonazepam and flunitrazepam.