NEW MATERIAL: A compd. represented by formula I [wherein (n) is 1 or 2; X is H, lower alkyl, lower alkoxy, halogen, OH, NO2 or CF3; R is H, benzyl or 2-12C alkanoyl (but a group-OR is not present at a first position of a tricyclic system); R1 and R2 are each H, lower alkyl, aryl-lower alkyl (but both of them are not aryl-lower alkyl at the same time) and combined to form a group represented by formula II (R3 and R4 are each lower alkyl)], its stereoisomer and its acid addition salt.

EXAMPLE: 9-Amino-1,2,3,4-tetrahydroacridineamin-4-ol.

USE: A medicine characterized by the lowering of choline acting function and useful for treating various memory function failures, for example, an Alzheimer's disease.

PROCESS: For example, a compd. represented by formula III and a compd. represented by formula IV are reacted to obtain a compd. represented by formula V being one of compds. represented by formula I.