ERROR opening https://cactus.nci.nih.gov/chemical/structure/C3CCCC3c%28nc2c1%3DO%29nc2n%28CCC%29c%28%3DO%29n1CCC/file?format=sdf&get3d=True  -- C3CCCC3c%28nc2c1%3DO%29nc2n%28CCC%29c%28%3DO%29n1CCC could not be loaded.