ERROR opening https://cactus.nci.nih.gov/chemical/structure/O%3DP%28O%29%28O%29Oc1cccc2c1c%28cn2%29CCN%28C%29C/file?format=sdf&get3d=True -- O%3DP%28O%29%28O%29Oc1cccc2c1c%28cn2%29CCN%28C%29C could not be loaded.