ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%28%3DC%28%5CC%29C%29%5CCNc1ncnc2c1%5BnH%5Dcn2/file?format=sdf&get3d=True  -- C%28%3DC%28%5CC%29C%29%5CCNc1ncnc2c1%5BnH%5Dcn2 could not be loaded.