1-Azido-4-fluoro-3-nitrobenzene 28166-06-5 4-Azido-1-fluoro-2-nitrobenzene 4-Fluoro-3-nitrophenyl azide BRN 1971081 Benzene, 1-azido-4-fluoro-3-nitro- Benzene, 4-azido-1-fluoro-2-nitro- CCRIS 4108 EINECS 248-878-6 FNPA NSC 266503