19-[(E)-4-Chloro-benzyl-idene]-16-(4-chloro-phen-yl)-2-hydr-oxy-1,11-diaza-hexa-cyclo-[15.3.1.0.0.0.0]henicosa-3(8),4,6-triene-9,18-dione

19-[(E)-4-Chloro-benzyl-idene]-16-(4-chloro-phen-yl)-2-hydr-oxy-1,11-diaza-hexa-cyclo-[15.3.1.0.0.0.0]henicosa-3(8),4,6-triene-9,18-dione