Synthesis of dipyrrolo[3,4-a:3,4-c]carbazole-1,3,4,6-tetraones bearing a sugar moiety

The synthesis of a series of dipyrrolo[3,4-a:3,4-c]carbazole-1,3,4,6-tetraones, structurally related to the G2 checkpoint inhibitor granulatimide and bearing a sugar moiety, is described. Substitutions were carried out at the 6-position of the glycosyl unit to lead to an amino substituent as observed in many biologically active compounds such as anthracyclins or staurosporines.