ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC1Nc4c%28OC1%28c2ccc%28O%29cc2%29c3ccc%28O%29cc3%29cccc4/file?format=sdf&get3d=True -- O%3DC1Nc4c%28OC1%28c2ccc%28O%29cc2%29c3ccc%28O%29cc3%29cccc4 could not be loaded.