4-pyridinecarboxylic acid, Pentafluorophenyl isonicotinate, isonicotinic acid pentafluorophenyl ester, Furyl-methyl-keton-isonicotinoylhydrazon, 4-Pyridinecarboxylic acid, [1-(2-furanyl)ethylidene]hydrazide, pyridine-4-carboxylic acid pentafluorophenyl ester, 1-furan-2-yl-ethanone isonicotinoylhydrazone