ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DC%28O%29%5BC%40%40H%5D%28N%29CCCNC%28%3DO%29N/file?format=sdf&get3d=True -- O%3DC%28O%29%5BC%40%40H%5D%28N%29CCCNC%28%3DO%29N could not be loaded.