ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%5C2%5CN%3DC%28/N%3DC1%5CC/2%3DN/NN1%29N/file?format=sdf&get3d=True -- O%3DC%5C2%5CN%3DC%28/N%3DC1%5CC/2%3DN/NN1%29N could not be loaded.