Komatsu_1995_Yakugaku.Zasshi_115_1022

The two dihydroxylated 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 the tricyclic diketone, 9-amino-2,3,6,7-tetrahydro-1H-cyclopenta[b]quinoline-1,8(5H)-dione, with equivalent molar of NaBH4, afforded the racemic two alcohols, (+/-)-9-amino-2,3,5,6,7,8-hexahydro-8-hydroxy-1H-cyclopenta[b]quinoli n-1-on e and (+/-)-9-amino-2,3,5,6,7,8-hexahydro-1-hydroxy-1H-cyclopenta[b]quinoli n-8- one. (+)-9-Amino-2,3,5,6,7,8-hexahydro-8-hydroxy-1H-cyclopenta[b]quinolin+ ++-1-one was obtained by optical resolution of the corresponding racemic hydroxyketone using (-)-di-p-toluoyl-L-tartaric acid. The optically active dihydroxylated metabolites were obtained by reduction of the (+)-8-hydroxy-1-one with NaBH4.