Chromatographic and spectroscopic properties of regioisomers of some 1H-1,5-benzodiazepines

The separation of the two regioisomeric derivatives of 1H-1,5-benzodia- zepine yielded from the reaction of 1,2-diamino-4-methylbenzene with 4-substituted acetophenones was performed by reversed phase high per- formance liquid chromatography, and the absorption spectra of the sepa- rated isomers have been determined for three isomer pairs which have been obtained starting from acetophenones with substituents of different electronegativity. The isomer ratio then could be estimated as well from the ratio of the peak areas as from the absorption spectra. They agree well with the known ratio determined from nmr intensities