ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1/C5H4N4/c1-4-5(8-2-6-1)9-3-7-4/h1-3H,(H,6,7,8,9)/f/h9H (9H-Purine)/file?format=sdf&get3d=True  -- InChI=1/C5H4N4/c1-4-5(8-2-6-1)9-3-7-4/h1-3H,(H,6,7,8,9)/f/h9H (9H-Purine) could not be loaded.