The present patent application discloses compounds having the formula ##STR1## or a pharmaceutically acceptable salt thereof or an oxide thereof wherein R.sup.3 is ##STR2## wherein A, B and D each is CH, or one or two of A, B and D is N and the others are CH;R.sup.11 is phenyl, benzimidazolyl, or monocyclic heteroaryl all of which may be substituted one or more times with substituents selected from alkyl, alkoxy, phenyl, halogen, CF.sub.3, amino, nitro, cyano, acyl, acylamino, phenyl and monocyclic heteroaryl; andone of R.sup.6 and R.sup.7 is hydrogen and the other is furanyl or isoxazolyl each of which may be substituted one or more times with substituents selected from halogen, alkyl, alkoxy and phenyl. The compounds are useful for the treatment of various central nervous system disorders such as epilepsy and other convulsive disorders, anxiety, sleep disorders and memory disorders.