ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C4H4N4/c1-3-6-8-7-4-2-5-1/h1-4H/b3-1-,4-2?,5-1-,5-2-,6-3?,7-4-,8-6-,8-7-/file?format=sdf&get3d=True  -- InChI=1S/C4H4N4/c1-3-6-8-7-4-2-5-1/h1-4H/b3-1-,4-2?,5-1-,5-2-,6-3?,7-4-,8-6-,8-7- could not be loaded.