Sulfanilic acid, synthesis

Chemists working with azo dyes use a shorthand designation based on the synthesis by azo coupling. It is characterized by an arrow from the amine used for diazotization (the so-called diazo component) to the coupling component, e. g., for 1.8 sulfanilic acid - 2-naphthol. This designation is especially useful for polyazo dyes (see Zollinger, 1991, p. 109). 

Figure 10. Synthesis of the 1,2- and 3,4-dihydrodiols of phen-anthrene from the related phenols by Method IV (47). Reagents (i) (KSO ) NO or (PhSe0>20 (ii) LiAlH or NaBH,, 0 (iii) di-azonium salt of sulfanilic acid (iv) Na O S (vJ (JrO. ...

Fig. 5.24. Regioselective azo coupling between diazotized sulfanilic acid and sodium 1-naphtholate (synthesis of Orange I).

The introduction of amino groups into phenols and ethers can be accomplished by the formation and reductive cleavage of their azo compounds. The diazotizing agent may be prepared from sulfanilic acid, and the reduction can be performed with sodium hydrosulfite. Excellent examples are found in the synthesis of l-amino-2-naphthol (85%) and 4-amino-l-naphthol (75%). ... 

In considering the synthesis of this compound several alternatives are possible. Two will be considered. Aniline may be sulfo-nated to sulfanilic acid, and after acetylation the chloride may be prepared by the action of phosphorus pentachloride. The acyl chloride, on ammonolysis, will give the acetylated sulfonamide. The other possibility is to use chlorosulfonic acid and introduce the sulfo and chloro groups simultaneously. Aniline is acetylated, and the acetanilide is sulfonated with excess of chlorosulfonic acid. The sulfonic acid group is introduced first, and by further reaction the acid chloride is formed ... 

Aldehyde synthesis. The reagent reacts with an alkyl- or arylmagnesium bromide to give a p-dimethylaminophenylcarbinol (1). This is easily cleaved by diazonium salts (diazotized sulfanilic acid was used because 3, Ar = p-H03SC6H4-, methyl orange is easy to eliminate). The products are the aldehyde (2) and an azobenzene... 

B Rubin. Studies on the induction of antibody synthesis against sulfanilic acid in rabbits, I. Effect of the number of hapten molecules introduced in homogeneous protein on antibody synthesis against the hapten and the new antigenic determinants. Eur J Immunol 2 5, 1972. 

AI3-15414 Aniline-4-sulfonic acid Aniline-p-sulfonic acid Aniline-p-sulphonic acid Benzenesulfonic acid, 4-amino- CCRIS 4576 EINECS 204482-5 HSDB 5590 Kyselina sulfanilova NSC 7170 p-Aminobenzenesulfonic acid Sulfanilic acid Sulfanilsaure Sulphanilic acid. Used in dyestuffs, organic synthesis, medicine. 

Monomer dihydroquinolines, the production of which is difficult, are required for the synthesis of tetrahydroquinolines moreover, an expensive catalyst is needed for this process - crystalline iodine. L. P. Zalukaev et al. [70] proposed that sulfanilic acid be used as a catalyst for this purpose in the condensation of the amine with acetone. According to the data of the authors, the addition of 1-2% sulfanilic acid to the reaction mass makes it possible to direct the reaction toward the formation of a large amovmt of the monomer, readily isolated by vacuum distillation. 

Waldschmidt-Leitz and Kuhn studied in detail the synthesis of hippurylanilide—the type of synthesis first foimd by Bergmann and associates. Using nearly equivalent amounts of hippuric acid and aniline, with papain as enzyme, there was 94% synthesis of the anilide. The equilibrium was approached from both sides. They could not obtain synthesis of hippurylamide from hippuric acid and ammonia the amide was completely and rapidly hydrolyzed. The condensation with hippuric acid occurred with aniline, o- m-, and p-toluidine, o- and p-aminophenol, o-anisidine, p-aminobenzoic acid, sulfanilamide, and o- and p-phenylene-diamine. The following compounds were inactive JV-methylaniline, o-aminobenzoic acid, sulfanilic acid, a-aminopyridine, adenine, benzyl-amine, cyclohexamine, and ammonia. 

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