ERROR opening https://cactus.nci.nih.gov/chemical/structure/n1cc%28nc1%29C%28c2c%28c%28ccc2%29C%29C%29C/file?format=sdf&get3d=True  -- n1cc%28nc1%29C%28c2c%28c%28ccc2%29C%29C%29C could not be loaded.