ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C6H8N2/c7-8-6-4-2-1-3-5-6/h1-5,8H,7H2/file?format=sdf&get3d=True  -- InChI=1S/C6H8N2/c7-8-6-4-2-1-3-5-6/h1-5,8H,7H2 could not be loaded.