ERROR opening https://cactus.nci.nih.gov/chemical/structure/CCNCC%28C1%26%2361%3BCC%28%26%2361%3BCC%26%2361%3BC1%29O%29O/file?format=sdf&get3d=True -- CCNCC%28C1%26%2361%3BCC%28%26%2361%3BCC%26%2361%3BC1%29O%29O could not be loaded.