ERROR opening https://cactus.nci.nih.gov/chemical/structure/CC%28C%29CN1C2%3DC%28C%28%3DO%29N%28C1%3DO%29C%29NC%28%3DN2%29COC/file?format=sdf&get3d=True -- CC%28C%29CN1C2%3DC%28C%28%3DO%29N%28C1%3DO%29C%29NC%28%3DN2%29COC could not be loaded.