Influence of the 2'-chloro substitution on central activity of desmethyldiazepam

Two diazepam derivatives, the N-desmethyl and the 2'-chlor-N-desmethyldiazepam, were compared in rats using behavioral and EEG techniques. Both drugs had depressant effects upon locomotor activity, facilitated behavior suppressed by punishment, increased the number of shocks received by rats in a Sidman avoidance procedure and caused a synchronization of EEG pattern lasting more than 7 h at the highest doses. The 2'-chlor-substituted compound was much more active than desmethyldiazepam potency ratio ranking between 3.67 and 20.78 according to the test employed.