Nitro group displacement and the reactivity of polynitroarylenes

Highly nitrated derivatives of benzene readily react with water to form phenols. 1,2,3,5-Tetranitrobenzene (54) is readily converted to picric acid on reaction with hot water. This type of reaction has practical concerns if such an explosive is used in a military context -picric acid forms dangerous picrates if allowed to come into contact with a metal surface i.e. the inside of a munition s shell. Other explosives like 2,3,4,6-tetranitrophenol (121) and 

6- tetranitrotoluene react with water to form 2,4,6-trinitroresorcinol (styphnic acid) and 

6- trinitro-m-cresol respectively. Some hindered nitro groups are displaced smoothly even at room temperature, and hexanitrobenzene (55), although a powerful explosive, is readily hydrolyzed to 2,4,6-trinitrophloroglucinol on reaction with water the latter is also formed from the reaction of water with 2,3,4,5,6-pentanitrophenol.  

The reactions of hexanitrobenzene (55) and 2,3,4,5,6-pentanitroaniline (31) with ammonia have been used to synthesize the thermally stable explosive l,3,5-triamino-2,4,6-trinitrobenzene (TATB). Holmes and Fliirschiem have studied the reactions of 2,3,4,5,6-pentanitroaniline with nucleophiles. 

Orlova and co-workers i reacted 1,2,3,5-tetranitrobenzene with hydrochloric and hydro-bromic acids to form picryl chloride and picryl bromide respectively. The same chemists treated 2,3,4,6-tetranitroaniline and 2,3,4,6-tetranitrophenol (121) with aqueous solutions of hydrogen halides to form 3-halo-2,4,6-trinitroanilines and 3-halo-2,4,6-trinitrophenols (122 and 123) respectively. 

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