A 13C-NMR assignment study of a series of 2,3,4,5-tetrahydro-1-methyl-1H-1,5-benzodiazepine-2,4-diones

The natural abundance ¹³C-nmr spectra of a series of 2,3,4,5-tetrahydro-1-methyl-1H-1,5-benzodiazepine-2,4-diones have been recorded: two of these compounds, clobazam and triflubazam, are clinically used as psychotherapeutic agents. The assignments of the various resonances have been made by chemical shift arguments, by the analysis of the fine splittings caused by one bond and long range couplings, and also by comparison with model compounds.