ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC1%3DCCC%28CC1%29C%28C%29%28C%29OC%28%3DO%29C/file?format=sdf&get3d=True -- CC1%3DCCC%28CC1%29C%28C%29%28C%29OC%28%3DO%29C could not be loaded.