2- Naphthalenesulfonic acid preparation

Naphthoresorcinol has been prepared by heating l-amino-3-hydroxy-4-naphthalenesulfonic acid or its salt in water or slightly acidic solution2 and by cyclization of ethyl phenylacetylmalo-nate 3 or of ethyl phenylacetoacetate.4 Phenylacetylmalonic ester has been prepared by condensing phenylacetyl chloride and malonic ester in ether with sodium.3... 

The 2-naphthalenesulfonic acid, l,2,3,4-tetrahydro-2-methyl-l,4-dioxo-, sodium salt, trihydrate can be prepared by mixing the 2-methyl-l,4-naphthoquinone with the bisulphite salt in the presence of water. Ordinarily gentle warming of the aqueous mixture is preferred to facilitate solution. The mixture of 2-methyl-l,4-naphthoquinone (250 mg 1 molar equivalent) sodium bisulphite (149 mg 1 molar equivalent) distilled water (250 ml) or 2-methyl-1,4-naphthoquinone (250 mg 1 molar equivalent) potassium bisulphate (349 mg 2 molar equivalent) distilled water 250 ml may be used. These examples representing preferred ratios of ingredients are merely illustrative and are not to be interpreted as limiting. 

Amino-l-naphthalenesulfonic acid 153 Preparation of the acid sulfate 70% Sulfuric acid (73.5 g) is heated to 120-125° in a three-necked flask fitted with a dropping funnel, stirrer, and descending condenser. A warm (50°) solution of 1-naphthylamine (75 g) in benzene (about 15 g) is then dropped in, with stirring, in 0.5 h the benzene distils off continuously. The solid residue is dried for 18 h at 120°. 

Amino-l-naphthalenesulfonic acid (Tobias acid) can be prepared homogeneously in 90% yield by using sulfur trioxide in tetrachloroethane.154... 

Examples of sulfonation by chlorosulfuric acid are the preparation of 2-hydroxy-1 -naphthalenesulfonic acid,124h 6-chrysenesulfonic acid,180 4-hydroxy-2-methylbenzenesulfonic acid.181 Aromatic amines are sulfonated with particular ease by this reagent. 

An extractant composed of the quaternary amine and dinonyl naphthalenesulfonic acid was chosen for further process development it is prepared by mixing the sulfonic acid with methyl tricaprylyl amine chloride [MT(OD)A, Aliquat-336 from Henkel, and washing with water to remove the HCl from the organic phase. This extractant shows sufficient capacity and good reversibility (see curve B in Fig. 17). An increase of the extractant concentration from 0.25 to 0.31 M and to 0.50 M increases the capacity proportionally. At the elevated temperature chosen for the process (about 80°C) the viscosity of the 0.50 M extractant is acceptable. Elevation of the temperature from 22 to 88°C has only a small effect on extraction efficiency. 

There has been greater synthetic activity in this series of fenestranes than in any other. The first simple member of the series to be prepared was tetraketone 69 . This synthesis by Cook, Weiss and their coworkers is the prototype of several studies by these investigators. In the case at hand, 70 could be cyclized to 69 in good yield in hot cumene-diglyme containing a large quantity of 1-naphthalenesulfonic acid. An X-ray study confirmed the structure of 69 and showed that in the crystal the molecule exists in a chiral... 

Fig. 3 Purification of550 mg of practical grade 4-hydroxy-1-naphthalenesulfonic acid by conventional HSCCC. a) HPLC analysis of the original material b) HSCCC elution profile of the separation and HPLC analyses of the separated components. Source From Preparative purification of 4-hydroxy-l-naphthalenesulfonic acid sodium salt by high-speed counter-current chromatography, in J. Chromatogr. A. ° ...

HeKajib 1,2,3-tributyl naphthalenesulfonic acid solution Active matter 16-20 % NaCl <0.7 % Prepared by sulfonating of alkyl naphthalene 1-10 % aqueous solution... 

What is the structure of 2-naphthalenesulfonic acid, and what function does it serve in the preparation of 4,4-dimethyl-2-cyclohexen-l-one ... 

The naphthalenesulfonic acids are important intermediates in the dyestuff industry for a complete account of their industrial preparation see Fierz-David and L. Blangey, "Grundlegende Operationen der Farbenchemie, 5th ed., J. Springer, Vienna, 1943. 

Levopropoxyphene [2338-37-6] (42), the optical antipode of the dextrorotatory analgetic propoxyphene, is an antitussive without analgetic activity. The 2-naphthalenesulfonate salt has a less unpleasant taste than the hydrochloride salt, and is widely used. Clinical effectiveness has been demonstrated against pathological and artificially induced cough, but the potency is somewhat less than codeine. The compound is reported not to cause addiction. Levopropoxyphene can be prepared (62) by first resolving [ -dimethylamino-CX-methylpropiophenone with dibenzoyl-(+)-tartaric acid. The resolved... 

Alkali fusion of sodium naphthalenesulfonate is one of the most important organic-technical operations. With the low price of naphthol, it is not surprising that only a few manufacturers undertake the preparation. Very cheap materials, such as coal, soda, and sulfuric acid, are essential. 

The described method of preparing diethyl jS-ketopimelate is a modification of that described by Bouveault and is essentially the same as that reported by Bardhan and Nasipuri. This ester has also been prepared by condensation of 7-carbethoxybutyryl chloride with ethoxymagnesiummalonic ester and cleavage of the resulting acylated malonic ester by (3-naphthalenesulfonic add or by acetic or propionic acids containing a trace of concentrated sulfuric acid. ... 

Amino acid 4-toluenesulfonate or 2-naphthalenesulfonate salts are esterified in high yield with diazodiphenylmethane in DMF (50 °C, 10min).P " l Diazodiphenylmethane is prepared by oxidation of benzophenone hydrazone, e.g. with yellow mercury(II) oxide in the presence of base, and can be stored in the dark.P P l In situ oxidation of the benzophenone hydrazone is performed with peracetic acid/l2 (trace) in the presence of the N-protected amino acids or peptides.P P l This method is not compatible with sulfur-containing amino acid residues. Alternatively, Dpm esters of protected amino acids and peptides are obtained using benzhydryl chloride or diphenylmethanol by standard esterification procedures. 

Of-Naphthoic acid has been prepared by the hydrolysis of a-naphthyl cyanide and (in poor yield) by the fusion of sodium a-naphthalenesulfonate and sodium formate. It has also been prepared by passing carbamyl chloride into naphthalene and aluminum chloride and hydrolyzing the a-napthamide thus formed.3... 

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