ERROR opening https://cactus.nci.nih.gov/chemical/structure/Cn1c%28%3DO%29cnn%28c1%3DO%29CCCCN2CCN%28CC2%29c3ncccn3/file?format=sdf&get3d=True -- Cn1c%28%3DO%29cnn%28c1%3DO%29CCCCN2CCN%28CC2%29c3ncccn3 could not be loaded.