2- nitro-4-aminophenol

GK [10343-58-5] (S ) (Cl Acid Yellow 99 Cl 13900) (4-nitro-2-aminophenol —> aceto acetanilide) and Palatine FastRedBEN [6656-02-6] (59) (Cl Acid Red 214 Cl 19355) (2-amiao-6-nitroplienol-4-sulfonic acid — 2,4-dihydroxyquiQoline). 

Mono- or diacyl derivatives that undergo cyclization to benzoxazoles on heating or under the influence of dehydrating agents are formed as intermediates in this reaction [134, 452, 453, 459, 461 173], Phosphorus oxychloride [453, 457], boric anhydride [455, 461, 462], or polyphosphoric acid [134, 471] are used as condensing agents. In particular, 2-hydroxy-5-nitrobenzoxazole, used for the synthesis of antivirus medicines, has been obtained by the reaction of condensation of 4-nitro-2-aminophenol with (NH2)2CO in pyridine [474],... 

Analogous Sulfonations. Exactly the same method can be used for sulfonating p-nitrochlorobenzene, p-nitrotoluene, o-m trochlorobenzene, chlorobenzene, and many other compounds. On the other hand, it is usually not possible to sulfonate dinitaro compounds in this way. Dinitrochlorobenzene and dinitrotoluene are decomposed explosively by treatment with fuming sulfuric acid. If dinitrochloro-benzenesulfoitic acid is to be prepared, for example, one starts with p-nitrochloro-benzene/ This is sulfonated, as described previously, and the sulfonic acid is converted to dinitrochlorobenzenesulfonic acid by treatment with mixed acid (50 50 sulfuric and nitric acids) at low temperatures. This product yields, on replacement of the chlorine by —OH and partial reduction, 4-nitro-2-aminophenol-6-sulfonic acid (nitro acid III), which is used in preparing chrome dyes. 

Nitro-2-aminophenol is diazotised in hydrochloric acid solution, treated with alkaline sodium nitrite, and warmed until the evolution of nitrogen ceases. The product is neutralised, filtered, and the filtrate evaporated to dryness in the presence of excess of hydrochloric acid. The residue is extracted with alcohol, boiled with charcoal and filtered. Yellowish cr3rstals of the nitro-acid separate out on cooling. It is decomposed on rapid heating, is soluble in alcohol, acetone, acetic acid, and hot water, sparingly soluble in cold water. The aqueous solutions of the alkali salts axe yellow. 

The uptake of 4-nitrocatechol and 4-nitro-2-aminophenol peaks at pH 6.5 and it is slightly depressed at high ionic strength. Low uptake of 4-mtro-I,2-phenylenediamme... 

Vasudevan, D. and Stone, A.T., Adsorption of 4-nitrocatechol, 4-nitro-2-aminophenol, and 4-nitro-l,2-phenylenediamine at the metal (hydr)oxide/water interface Effect of metal (hydr)oxide properties, J. Colloid Intetf. Sci., 202, 1, 1998. 

Hydroxy-5-nitroaniline 4-Nitro-2-aminophenol p-Nitro-o-aminophenol Phenol, 2-amino-4-nitro-... 

Unfortunately, length restrictions did not permit us to consider in detail the tremendous amount of information available on heteroleptic complexes, which are briefly reviewed in Chapter 7. The reviews do not consider a broad group of autocomplexes — derivatives of nitro-, aminophenols, ketoenols, and also chloro-, bromo-, and iodophenols that are stable to hydrolysis and are only formal analogs of alkoxides and phenoxides. 

Nitro- aminophenol-6 sulfonic acid (mtro acid III)... 

Reduction to aminophenol. Reduce about 0 5 g. of o-nitrophenol with cone. HCl and tin as described on p. 385. After a few minutes the yellow molten o-nitrophenol disappears completely, the solution becoming homogeneous and colourless due to the formation of 0-aminophenol (which is soluble in HCl). Cool and add 30% aqueous NaOH solution note that a white precipitate is first formed and then redissolvcs in an excess of NaOH, and that the solution does not develop an orange coloration, indicating that the nitro-group has been reduced. 

Also present but not essential in permanent hair colorants are nitro dyes which dye hair without oxidation. These dyes, nitro derivatives of aminophenols and benzenediamines, impart yellow, orange, or red tones. Although they have good tinctorial value, they are not as colorfast as the oxidative dyes. They also are used in semipermanent hair colorants. 

Electrolytic reductions generally caimot compete economically with chemical reductions of nitro compounds to amines, but they have been appHed in some specific reactions, such as the preparation of aminophenols (qv) from aromatic nitro compounds. For example, in the presence of sulfuric acid, cathodic reduction of aromatic nitro compounds with a free para-position leads to -aminophenol [123-30-8] hy rearrangement of the intermediate N-phenyl-hydroxylamine [100-65-2] (61). 

Insoluble red lakes are formed as by-products which decrease yields when 2-nitrophenol [88-75-5] is reduced with iron. Consequendy, the iron reduction of this nitro compound to 2-aminophenol is of minor industrial importance today. 

Nitro benzene C6H5NO, Production of aniline, para-aminophenol, and dyes... 

Recently, the substituent effect on the diazotization of substituted 2-aminophenols was studied53 in aqueous hydrochloric acid solution. When the substituent is strongly electron-withdrawing, such as a nitro group, the diazotized product deprotonates and forms a substituted 1,2-benzoquinone-l-diazide which usually precipitates. 

Nitro alcohols were reduced to amino alcohols by catalytic hydrogenation over platinum [632] and with iron [JJ9], and nitrosophenols [255] and nitro-phenols [256] to aminophenols with sodium hydrosulfite, sodium sulfide [238] or tin [176]. Bromine atoms in 2,6-di-bromo-4-nitrophenol were not affected [176]. 

A nitro group at the meta position is readily hydrolysed in water to the phenolic group with the formation of the nitro derivative of N-methyl-m-aminophenol (VIII). Since technical dimethylaniline usually contains a certain amount of methylaniline,... 

Glowiak [20] examined the properties of the diazotization products of numerous nitro derivatives of o-aminophenol, viz. ... 

The nitro groups in 3,5-dinitrodiaryl ethers may be readily replaced with the residues of mono-and bis-phenols. The simplest 3,5-dinitrodiaryl ether - 3,5-dinitrodiphenyl ether - was reacted with 4-aminophenol or 4-acetamidophenol with the formation of 3-nitro-5-[4-amino(amido)]-phenoxydiphenyl ether subsequent transformation of this product led to 3-amino-5-(4-aminophenoxy)-diphenyl ether [24] (Scheme 4.9). 

Nitro-4-methoxyaniline has been prepared by heating nitro-hydroquinone dimethyl ether with aqueous ammonia 2 by heating the tetramethylammonium salt of 3-nitro-4-aminophenol 3 by the hydrolysis of 2-nitro-4-methoxyacetanilide la with alcoholic potassium hydroxide 11 lc or hydrochloric acid ld and by the hydrolysis of the />-toluenesul fonamide,4 the 3-nitrobenzenesul-fonamide,5 the 3-nitro-/>-toIuenesulfonamide,3 and the acetyl derivative of the />-toluenesulfonamide6 of 2-nitro-4-methoxyani-line with concentrated sulfuric acid. 

EXPLOSIVES AND PROPELLANTS - EXPLOSIVES] (Vol 10) 6-Nitro-2-aminophenol-4-sulfomc acid [96-93-5]... 

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