New compounds of the formula: ##SPC1##Wherein A is a phenyl, pyridyl, pyridazinyl, 2-, 3- or 4-quinolyl or naphthyridinyl radical, or a said radical substituted by one or two atoms or radicals selected from halogen, alkyl, alkoxy cyano and nitro, R is alkyl, alkenyl or hydroxyalkyl, and n is zero or 1, possess pharmacological properties and are, in particular, active as tranquilisers, anti-convulsant agents, decontracturants and agents to produce hypnosis.