A compound selected from the group consisting of racemates, enantiomeric and diastereoisomeric forms of a compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 are individually selected from the group consisting of hydrogen and alkyl of 1 to 5 carbon atoms optionally substituted with at least one halogen, hydroxy, alkyl or alkoxy of 1 to 4 carbon atoms or taken together with the nitrogen to which they are attached form a heterocycle optionally containing a heteroatom selected from the group consisting of --O--, --S-- and nitrogen optionally substituted with alkyl or alkoxy of 1 to 5 carbon atoms, optionally substituted benzyl and phenyl, R.sub.3 and R.sub.4 are individually selected from the group consisting of hydrogen, halogen, hydroxy and alkyl and alkoxy of 1 to 5 carbon atoms optionally substituted with at least one substituent selected from the group consisting of halogen, hydroxy, phenyl and alkyl and alkoxy of 1 to 4 carbon atoms, R.sub.5 is hydrogen or alkyl of 1 to 5 carbon atoms optionally substituted with at least one member of the group consisting of halogen, hydroxy, phenyl and alkyl and alkoxy of 1 to 4 carbon atoms and its non-toxic, pharmaceutically acceptable acid addition salts and quaternary ammonium salts having analgesic activity and their preparation.