ERROR opening https://cactus.nci.nih.gov/chemical/structure/CN%28C%29C%28%3DS%29SSC%28%3DS%29N%28C%29C/file?format=sdf&get3d=True -- CN%28C%29C%28%3DS%29SSC%28%3DS%29N%28C%29C could not be loaded.