6-amino-4-hydroxy-2-naphthalene-sulfonic

Heterocycles are known to have O—S, S—N, and O—N bonds. The cyclization of peri-hydroxy and peri-amino-substituted naphthalene sulfonic acids gives rise to 1,8-naphthosultone 246 and 1,8-naphthosultam 247, respectively (33MI2 63MI1). On gas phase photolysis of naphtho[/>c]-... 

Amino-3-hydroxy-7-nitro-l-naphthalene-sulfonic acid [6259-63-8]... 

A particularly important class of coupling components are the aminohydroxy-naphthalenesulfonic acids. Appropriate variation of the disazo component permits the development of shades ranging from orange to black. Orange and scarlet are achieved with I-acid (6-amino-l-hydroxy-naphthalene-3-sulfonic acid) and y-acid (7-amino-1-hydroxynaphthaIcne-3-sulfonic acid), whereas H-acid (8-amino-l-hydroxynaphthalene-3,6-disulfonic acid) and K-acid (8-amino-l-hydroxy-naphthalene-3,5-disulfonic acid) derivatives are useful for red to bluish-red hues. Extremely lightfast red shades are also accessible with disazo dyes ( brown dyes ). For chemical structures see Section 3.1.5). 

Alkaline glucose converts the diazonium salts of l-amino-2-hydroxy-naphthalene-4-sulfonic acid and its halogen, nitro, carboxyl, or sulfonic acid derivatives into the corresponding 2-hydroxynaphthalene-4-sul-fonic acids.126 According to this patent, the yields are nearly quantitative. 

Acetylamino-2-sulfophenylazo)-6-amino-4-hydroxy naphthalene-2-sulfonic acid, disodium salt. See Acid red 37... 

Naphthalenesulfonic acid, 6-amino-4-hydroxy-5-((2-(trifluoromethyl) phenyl) azo)-, monosodium salt. See Acid red 337 Naphthalenesulfonic acid, bis-(l-methylethyl)-, sodium salt. See Sodium isopropyl naphthalene sulfonate... 

Mahmoud, M.E. Soayed, A.A. Hafez, O J. Selective sohd phase extraction and pre-concentration of heavy metals from seawater by physicahy and chemicahy immobilized 4-amino-3-hydroxy-2-(2-chlorobenzene)-azo-l-naphthalene sulfonic acid silica gel. Microchim. Acta 2003,143 (1), 165. 

The term coupling component referred originally to aromatic hydrocarbons, particularly benzene and naphthalene derivatives, which were required to have a hydroxy or an amino group as a substituent (sometimes, but not necessarily, accompanied by other substituents such as sulfonic acid groups). The presence of the hydroxy or amino group increases the C-nucleophilicity of the coupling component. In most cases this is a necessary requirement because the diazo components are relatively weak electrophiles. If the coupling component is phenol or a derivative of phenol ... 

Reaction of a similar triazine component with I acid (1-hydroxy-6-amino-naphthalene-3-sulfonic acid), followed by coupling with diazotized 4-aminoazo-benzene gives the cationic substantive azo dye 4 [71032-95-6], which colors paper in red hues. 

Naphthalene-2-sulfonic acid p-Naphthalenesulfonic acid. See 2-Naphthalenesulfonic acid 2-Naphthalenesulfonic acid, 6-((7-amino-1-hydroxy-3-sulfo-2-naphthalenyl) azo)-3-((4-((4-amino-6 (or 7)-sulfo-1-naphthalenyl) azo) phenyl) azo)-4-hydroxy-, trisodium salt. See Direct black 80... 

The sulfonation of amino and hydroxy derivatives of naphthalene usually leads to a large number of isomers. To avoid isomer formation as much as possible, naphthionic acid often is prepared by baking the sulfate of 1-naphthylamine. 

Dimethylpheny[)amino carbonyl]-2-hydroxy-l-naphthalenyl]azo] 4-hydroxybenzenesulfonic acid, 9CI. 1-Azo-2-hydroxy-3- 2,4-dimethylcarboxanilido)naphthalene- r - 2-hydroxybenzene-5-sulfonic acid). Xylidyl blue I [36505-52-9]... 

Hydroxy-2-(4-amino-l,2,4-triazol-3-ylazo)naphthalene-4-sulfonic acid (C2 2 904N S)... 

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