3-amino-2,4,6-trinitrophenol

Nitration of m-nitroaniline (28) with fuming nitric acid and oleum yields 2,3,4,6-tetranitroaniline (29), a powerful but chemically unstable explosive. 2,3,4,6-Tetranitroaniline readily reacts with a range of nucleophiles, including water to yield 3-amino-2,4,6-trinitrophenol. 

Trinitro-3-aminophenol (TNAPh) or 3-Amino-2,4,6-trinitrophenol or 3-Amino-picric Acid. Yel-bm flat ndls (from ale), mp 178-180°(was reported by Blanksma as 218° and in Ref 5 as 222-3°) nearly in sol in cold ale or w, si sol in hot ale or benz. Several methods of prepn are described in the literature. C. F.van Duin et al (Ref 3) prepd it by treating an acetonic soln of tetranitroaniline with an aq soln of CHjCOONa at RT- Several other methods are given in Refs 1, 2 4... 

In a recent patent(Ref 5) is described the method of prepn of 3-amino-2,4,6-trinitrophenol, mp 222-3° from 3-chlotopicric acid and gaseous NH ... 

Yellow to brown compounds are obtained when one or more nitro groups are conjugated with electron-donor substituents such as hydroxy or, of more importance, amino groups. Such dyes are relatively cheap. Picric acid, 2,4,6-trinitrophenol, can be regarded as the oldest synthetic dye it was produced in 1771 by Woulfe by treating indigo with nitric acid. 

Carboxy-l,3-diamino-2,4,6-trinitrobenzene 5-Nitro-2(3,5-diamino-2,4,6-trinitrophenol)-1,2,4-triazole 5-Nitroterazolecopper salt 5-Ureido-l,3-diamino-2,4,6-trinitrobenzene 7-Amino-4,6-dinitrobenzofuroxan 10-Chloro-5,10-dihydrophenarsazine Acetyltrinitro-cyclotetramethylene tetramine Acquinite... 

Explosives and related compounds have become widely recognized as serious environmental contaminants. Among the nitrosubstituted aromatic compounds causing particular concern are 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (picric acid), and many nitro- and/or amino-substituted aromatics that result from the manufacture and transformation of explosives. The threat posed by the presence of these compounds in soil and water is the result of their toxicity and is compounded by their recalcitrance to biodegradation. 

Reduction of the 2-nitro in 2,4,6-trinitrophenol yields picramic acid, 2-amino-4,6-dinitrophenol. It is highly explosive but safe to handle when wet. It was also an important intermediate in dye manufacture. Centralite, a stabilizer in smokeless powders, is made from monoethylaniline. 

Finally 2,4,6-trinitrophenol (2,4,6-TNP), picric acid, is used as explosive under the form of ammonium 2,4,6-trinitrophenoxide. Both picric acid and picramic acid (2-amino-4,6-dinitrophenol), deriving from the bioconversion of picric acid imder anaerobic conditions, are well-known mutagenic compounds [73]. 

---