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