ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C6H8O2/c1-4-2-3-5(7)6(4)8/h8H,2-3H2,1H3/file?format=sdf&get3d=True  -- InChI=1S/C6H8O2/c1-4-2-3-5(7)6(4)8/h8H,2-3H2,1H3 could not be loaded.