ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C5H6N2/c1-5(2,3-6)4-7/h1-2H3/file?format=sdf&get3d=True  -- InChI=1S/C5H6N2/c1-5(2,3-6)4-7/h1-2H3 could not be loaded.