3,4-diaminoquinoline and 3,4-diamino-5,6,7,8-tetrahydroquinoline

Abstract

4-aminopyridine derivatives represented by the general formula: ##STR1## [wherein R.sub.1 is a hydrogen atom, a hydroxyl group, a linear or branched lower alkyl group or a cycloalkyl group which may be substituted by a hydroxyl group, a lower alkoxy group, a lower alkyl or a cycloalkyl group which contains a carbonyl group, a morpholino group or a group --NH--B (where B is a lower alkyl group, a cycloalkyl group or a phenyl group); R.sub.2 and R.sub.3 which may be the same or different each represents a hydrogen atom, a lower alkyl group or a loweralkylcarbonyl group, or when taken together, form an azacycloalkyl group, a morpholino group or an N-methylpiperazinyl group together with the nitrogen atom; R.sub.4 and R.sub.5 each represents a hydrogen atom, or when taken together with the ring A, form a quinoline ring or a 5,6,7,8-tetrahydroquinoline ring, provided that when each of R.sub.1, R.sub.4 and R.sub.5 is a hydrogen atom, R.sub.2 and R.sub.3 are neither a hydrogen atom nor a methyl group at the same time, and when R.sub.1 is a hydrogen atom and R.sub.4 and R.sub.5 taken together with the ring A form a quinoline ring, R.sub.2 and R.sub.3 are neither a hydrogen atom nor an ethyl group at the same time], and an acid addition salts of said 4-aminopyridine derivatives. These compounds are useful as active ingredients in pharmaceutical compositions for improving psychoneural function, especially in the treatment of Alzheimer type dementia and promotion of mnemonic and learning performance.