Crystal structure and conformational analysis of doxorubicin nitrate.

Crystal structure determination of doxorubicin nitrate, (DoxH)NO3 , systematic name (7 S ,9 S )-7-{[(2 R ,4 S ,5 S ,6 S )-4-azaniumyl-5-hy-droxy-6-methyl-oxan-2-yl]-oxy}-6,9,11-trihy-droxy-9-(2-hy-droxy-acet-yl)-4-meth-oxy-8,10-di-hydro-7 H -tetra-cen-5,12-dione nitrate, shows two formula units present in the asymmetric unit. In the crystal lattice, hydrogen-bonded pairs of (DoxH+ ) cations and segregation of the aglycone and sugar moieties are observed. Inspection of mol-ecular overlays reveals that the conformation of (DoxH)NO3 resembles that of DNA-inter-calated, but not of protein-docked (DoxH)+ . The structure was refined as a two-component twin.