ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1COCCN1CNC%28%3DO%29C2%3DNC%3DCN%3DC2/file?format=sdf&get3d=True -- C1COCCN1CNC%28%3DO%29C2%3DNC%3DCN%3DC2 could not be loaded.