CAS 123871-59-0: 2,5-Cyclohexadien-1-one,4-fluoro-4-nitro-(9CI)

4-Fluoro-4-nitro-2,5-cyclohexadien-1-one (4FCH) is a dienone that can be prepared by nitration of 4-(nitro)phenol. It is also produced when acetates are heated with nitric acid in the presence of metallic catalysts. The reaction is exothermic and can be carried out at temperatures below 100°C. 4FCH isomerizes to 2,5-dihydrobenzoquinone on heating and reacts with nitrous acid to form 3,4,5,6-tetranitrobenzoquinone (TNBQ).