ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1CC%28C2%3DCC%3DCC%3DC2C1%29C3%3DNCCN3/file?format=sdf&get3d=True  -- C1CC%28C2%3DCC%3DCC%3DC2C1%29C3%3DNCCN3 could not be loaded.