The invention concerns new compounds of the formula (I) ##STR1## wherein R.sup.1 is hydrogen, phenyl or phenyl substituted with at least one alkyl having 1 to 4 carbon atoms, halogen, alkoxy having 1 to 4 carbon atoms or nitro;R.sup.2 is alkyl having 1 to 4 carbon atoms, cycloalkyl having 5 to 7 carbon atoms, phenyl, or phenyl substituted with at least one alkyl having 1 to 4 carbon atoms, halogen, alkoxy having 1 to 4 carbon atoms or nitro;R.sup.3 is alkoxy having 1 to 4 carbon atoms or hydrogen,R.sup.4 is hydrogen, alkyl having 1 to 4 carbon atoms unsubstituted or substituted with alkoxy having 1 to 4 carbon atoms, benzyloxy or cyano, phenyl, or phenyl substituted with at least one alkyl having 1 to 4 carbon atoms, halogen, alkoxy having 1 to 4 carbon atoms or nitro, or phenyl-(C.sub.1-4 alkyl)-alkyl, in which the phenyl moiety may bear an alkoxy substituent having 1 to 4 carbon atoms or a halogen;m and n are each 0, 1 or 2 or a pharmaceutically acceptable acid addition or quaternary salt thereof.The compounds are potent vasodilators and exert a favorable influence on the extremital blood flow. They also show a heart function influencing activity.Methods for the preparation of said compounds and pharmaceutical compositions containing them are also the subject of the invention.