This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl)aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C-R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl group and acid addition salts thereof.Also provided are methods for their preparation and intermediates thereof. These compounds exhibit activity as anticonvulsants, muscle relaxants and sedatives.