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The synthesis of two dihydroxylated metabolites of NIK-247 has been reported: Two diastereomeric isomers 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline-1,8-diol (VI) and (VII) have been synthesized as follows. The oxidation of 2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-9-amine (I) with CrO3.H2SO4 gives 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline-1,8-dione (II), which is selectively reduced with 1 equivalent of NaBH4 yielding a mixture of the two hydroxyketones (III) and (IV), separated by crystallization. The optical resolution of (III) with (-)-di-p-toluyltartaric acid affords the pre (+)-isomer (V), which is further reduced with NaBH4 to afford a diastereomeric mixture of the 1,8-diols (VI) and (VII), which is separated by HPLC over Chiracel OG in n-hexane ethanol (9:1).