Novel aminoisoquinoline derivatives of the general formula (I) ##STR1## wherein R.sub.1 represents a hydrogen atom or a C.sub.1-4 alkyl group, R.sub.2 represents a hydrogen atom, R.sub.3 represents a hydrogen atom, R.sub.4 represents a morpholinyl group or a piperazinyl group substituted with a pyridyl group, and pharmaceutically acceptable acid addition salts and quaternary derivatives thereof have been prepared. The novel compounds exert narcosis potentiating effects.
3-hydroxyisoquinolines have been carried out to provide newfluorescentderivatives. The transformations involved nucleophilic substitution of a bromine atom or a triflate moiety at positions 1 and 3, respectively, as well as the condensation reaction of a 3-amino group with triethyl orthoformate and subsequent transformation with amines to give amidines. The new compounds have been studied by fluorescence spectroscopy