Abstract: The invention provides new compounds of the formula ##STR1## in which one of the symbols R.sub.1 and R.sub.2 denoted a hydrogen atom and the other a hydroxyl group or, together, the two denote an oxygen atom, and R.sub.3 denotes an alkenyl group having 3 to 6 carbon atoms, a cyclohexyl group, or an aminoalkyl group in which the alkyl group has from 1 to 3 carbon atoms and the amino group is a morpholino, 4-methylpiperazino or piperidino radical, as well as the pharmaceutically acceptable addition salts of the compounds containing an amino group, which are useful as tranquilizers, anticonvulsants and anti-depressants.