ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC%28C%29%3DCCCC1%3DCCC%28C%29%28C%3DO%29CC1/file?format=sdf&get3d=True -- CC%28C%29%3DCCCC1%3DCCC%28C%29%28C%3DO%29CC1 could not be loaded.