The two mono-hydroxylated metabolites of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline monohydrochloride monohydrate (NIK-247), which is a new drug for the treatment of dementia, were synthesized to determine their chemical structures. Reduction of two tricyclic ketones, 9-amino-1,2,3,5,6,7-hexahydro-8H-cyclopenta[b]quinolin-8-one and 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]-quinolin-1-one, with NaBH4 afforded the corresponding racemic alcohols. The optically active mono-hydroxylated metabolites, (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-8-ol and (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-1-ol, were obtained by optical resolution of each racemic alcohol using (+)-di-p-toluoyl-D-tartaric acid.