ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C4H4N2O4/c7-1-2(8)5-4(10)6-3(1)9/h7H,(H3,5,6,8,9,10)/file?format=sdf&get3d=True  -- InChI=1S/C4H4N2O4/c7-1-2(8)5-4(10)6-3(1)9/h7H,(H3,5,6,8,9,10) could not be loaded.