Naphthalene Anthranilic acid from

Among substances that are sublimed under vacuum are anthranilic acid, hydroxyanthraquinone, naphthalene, and fl-naphthoi. Pyrogallol and d-camphor distill from the liquid state but condense as solids. Several metals are purified by sublimation, for instance, magnesium at 600°C and 0.01-0.15 Torr. 

The details of this synthesis will be explained under naphthalene (p. 766). The synthesis of anthranilic acid from ortho-i hthalic acid takes place according to the following reactions. Phthalic acid, or better phthalic anhydride, by treatment with ammonia yields phthal-amidic acid, which in turn yields phthalimide. 

This was the first practical approach to the manufacture of the dye (123). The patent to this process was shared joindy by BASF and Hoechst (124). The yields by this process were so bad that Heumann developed another process involving the use of anthranilic acid [118-92-3] (39) (made from naphthalene). 

Elkana et al. [138] made a careful study of the transfer of energy from excited naphthalene donor molecules to anthranilic acid acceptor molecules by observing the acceptor and donor fluorescence intensities when the donor was excited with continuous radiation (A = 272nm). The solvents were changed from glycerol to increasingly more and more... 

The intramolecular Diels-Alder addition of a benzyne to a furan has been exploited in a synthesis of mansonone E (81TL4877). The benzyne (211), generated from the anthranilic acid (210), yields the adduct (212 86%) which is easily converted into the naphthalene (213 Scheme 79). A similar addition was achieved by generating the benzyne by treating an o -dibromobenzene with butyllithium. 

Synthesis from Phthalic Acid and Naphthalene.— This was found when anthranilic acid was synthesized from ortho-phthalic acid which, as has been stated, may in turn be synthesized from naphthalene, a cheap abundant compound. The conversion of naphthalene into or//fo-phthalic acid we have given (p. 689) as resulting from chlorination and subsequent oxidation. 

Indigo is manufactured in large quantities by a synthesis which involves the use of naphthalene and acetic acid. From the former anthranilic acid (605) is prepared and from the latter chloroacetic acid. These compounds react to form phenyl-glycocoll-o-carboxylic acid —... 

These include prolinamides derived from anilines 2a-c,h, 2-hydroxyanilines 2d-f, o-diaminobenzene derivatives 2g, amino-naphthalene ferrocenylamines 11, anthranilic acid-based pro-... 

The so-called second Hemnann indigo synthesis started from anthranilic acid rather than aniline, and gave substantially better yields. Anthranilic acid was accessible by oxidation of naphthalene to phthalic anhydride, after Hoogewerf and van Dorp had shown that Hofmann degradation of the halfamide of phthalic acid leads to the desired product. 

Among later syntheses of indigo was that from phenylglycine carboxylic acid by Heumann. This was first made from aniline, but its preparation from naphthalene made the process technically workable. The research was carried out for the Badische Co. by their chemist E. Sapper (1891-7) and depended on the oxidation of naphthalene to phthalic acid by heating with concentrated sulphuric acid in presence of mercury as a catalyst (said to have been discovered accidentally by the breaking of a thermometer bulb). Phthalic acid was converted into phthalic anhydride, phthalimide, and anthranilic acid, and phenylglycine carboxylic acid by condensation of this with chloracetic acid. On fusion with caustic potash, or better sodamide, this formed indoxylic acid, and indoxyl, which was easily oxidised to indigo. 

Methyl anthranilate (41) is synthesized from either naphthalene (200) or o-xylene (201) as shown in Figure 6.34. Oxidation of either starting material produces phthalic acid (202). Conversion of this diacid to its imide, followed by the Hoffmann reaction, gives anthranilic acid, and the methyl ester can then be obtained by reaction with methanol. 

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