ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1%3DCC%3DC2C%28%3DC1%29C%28%3DNN%3DC2NN%29NN/file?format=sdf&get3d=True -- C1%3DCC%3DC2C%28%3DC1%29C%28%3DNN%3DC2NN%29NN could not be loaded.