Abstract
Oxazepam (CAS 604-75-1) 4a served as building block in the synthesis of substituted
3-amino-1,4-benzodiazepines, which were subsequently tested in various CNS animal
models. The hydroxy group of oxazepam was either activated as a chloride (Method A)
or as a phosphor-oxy derivative (Method B) giving the desired 3-amino-1,4-benzodiapines
6a–6r in high yields with primary and secondary amines in a typical nucleophilic substitution
reaction. Eighteen 3-substituted 1,4-benzodiazepines were prepared and served as new
chemical entities and for lead structure discovery. The mixed cholecystokinin (CCK)
antagonist 6e showed anxiolytic and antidepressant effects from 10 μg/kg in mice in
the elevated x-maze test and the forced swimming test. The CCK1 antagonist 6 g has shown antidepressant effects from the same dose, but lacked anxiolytic
properties. Both compounds potentiated at a dose of 0.5 mg/kg morphine antinociception
with a maximum possible effect (MPE) about 35%. By assessing initially the MPE of
antinocipection for the 18 newly synthesised benzodiazepines in the tail-flick test,
4 other benzodiazepines were found active. In further in vivo evaluation the cyclohexyl derivative 6i displayed anxiolytic, antidepressant and
antinociceptive properties as single agent at a dose of 5 mg/kg without toxicity.
The benzodiazepines 6i and 6p, which initially showed a higher MPE in terms of morphine
potentiation (43/44%) showed analgesic effects as single agents, without having anxiolytic
or antidepressant properties.
The amino-piperidinyl derivative 6p displayed a similar dose-response relationship
to morphine, but was 3 times more potent.
Key words
3-Amino-5-phenyl-l,4-benzodiazepinone - Antidepressants - Antinociceptives - Anxiolytics
- 1,4-Benzodiazepines, template - CAS 604-75-1 - Cholecystokinin antagonists - Oxazepam