1-fluoro-2,4-dinitro-benzene 1-fluoro-2,4-dinitrobenzene 2,4-dinitrofluorobenzene 70-34-8 FDNB InChI=1/C6H3FN2O4/c7-5-2-1-4(8(10)11)3-6(5)9(12)13/h1-3 Sanger's Reagent benzene, 1-fluoro-2,4-dinitro-