1-[(6-Chloro-pyridin-3-yl)meth-yl]-10-nitro-1,2,3,5,6,7,8,9-octa-hydro-5,9-methano-imidazo[1,2-a]azocin-5-ol.

In the title compound, C16H19ClN4O3, the cyclo-hexane ring displays a chair formation and the tetra-hydro-pyridine ring displays an envelope conformation with the methyl-ene C atom as the flap; the imidazolidine ring also displays an envelope conformation with a methyl-ene C atom as the flap. In the crystal, O-H⋯N hydrogen bonds between hy-droxy groups and pyridine rings link inversion-related mol-ecules into dimers. Weak C-H⋯O hydrogen bonds further link the dimers into supra-molecular chains running along the c axis.