New compounds of the general formula (I) ##SPC1##whereinR.sub.1 and R.sub.2 each is a saturated or unsaturated, straight-chained or branched alkyl group, an aralkyl group, a saturated or unsaturated cycloalkyl group or an aryl group, orR.sub.1 and R.sub.2 together with the adjacent nitrogen atom may form substituted or unsubstituted heterocyclic group with or without a further oxygen or nitrogen heteroatom, andR.sub.3 is hydrogen or an acyl group derived from a C.sub.1.sub.-18 carboxylic acid.The compounds are prepared by reducing the corresponding nitro compounds of the general formula (II) ##SPC2##and optionally acylating the obtained product.The compounds of the general formula (I) and their acid addition salts and quaternary ammonium salts are active primarily in the induction of liver microsomal enzyme, but they also possess valuable antipyretic activity and a yohimbine lethality increasing effect characteristic of antidepressants.