This invention encompasses compounds of the formula: ##STR1## and the pharmaceutically acceptable non-toxic salts thereof wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 are variables;X and Y represent hydrogen, halogen, hydroxy or amino substituents, with the proviso that when Y is a hydrogen, halogen, or amino substituent, X is hydroxy; andW represent aryl groups unsubstituted or substituted with halogen, hydroxy, alkyl, alkoxy or amino groups.These compounds or prodrugs thereof are highly selective agonists, antagonists or inverse agonists or GaBAa brain receptors or prodrugs thereof and are useful in the diagnosis and treatment of anxiety, sleep, and seizure disorder, overdose with benzodiazepine drugs, and enchancement of memory.