ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%28c1ncn2C%28%3DO%29N%28%5CN%3DN/c12%29C%29N/file?format=sdf&get3d=True -- O%3DC%28c1ncn2C%28%3DO%29N%28%5CN%3DN/c12%29C%29N could not be loaded.