CORRELATION BETWEEN BIOLOGICAL-ACTIVITY AND ENERGIES OF ELECTRONIC-TRANSITIONS IN BENZODIAZEPINES - NEGATIVE-ION MASS-SPECTROMETRY STUDY OFBR-SUBSTITUTED DERIVATIVES

In order to find which of the electron structure features of benzodiaz epine molecules control their biological activity, a series of benzodi azepine derivatives was investigated by means of negative ion mass spe ctrometry with resonance electron capture. The resonance curves for ne gative ion effective yields are presented. Comparison within a series demonstrates a significant (0.6-1.5 eV) shift of curve maxima towards high electron energies (destabilization) for inactive compounds. It is concluded that the destabilization of resonances reflects an increase in energy of several first electronic transitions in the neutral benz odiazepine molecules, and is related to the second (inactive) conforme r, the pseudo-chair. It is suggested that the energies of the electron ic transitions are the sought feature of the electron structure of a b enzodiazepine molecule which correlates with its activity, and that th e stereospecific structure of the benzodiazepine conformers affect the activity via this feature. (C) 1998 John Wiley & Sons, Ltd.