ERROR opening http://cactvs.nci.nih.gov/chemical/structure/CC%28C%29%28C%29C1%3DNN%3DC%28N%28C1%3DO%29N%29SC/file?format=sdf&get3d=True -- CC%28C%29%28C%29C1%3DNN%3DC%28N%28C1%3DO%29N%29SC could not be loaded.