ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCC%28c1ccccc1%29%28C%28%3DO%29N%29C%28%3DO%29N/file?format=sdf&get3d=True -- CCC%28c1ccccc1%29%28C%28%3DO%29N%29C%28%3DO%29N could not be loaded.