• B S Joshi

      Articles written in Proceedings – Section A

    • Anthraquinone and anthrone series - Part V. Chlorinated 6-aminoanthraquinoneacridones

      B S Joshi B D Tilak K Venkataraman

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      Indanthrene Turquoise Blue GK and 3GK have been shown to be 11-chloro-6-aminoanthraquinoneacridone (II) and 10∶12-dichloro-6-aminoanthraquinoneacridone (III) respectively by unambiguous synthesis. The absorption spectra of the commercial and the synthetic dyestuffs have been determined. Chloro derivatives of 6-aminoanthraquinoneacridone, substituted by chlorine in the anthraquinone nucleus, in the benzene half of the molecule, and in both the anthraquinone and the benzene halves, have been synthesised, and the fastness properties of the shades on cotton determined. 6-Aminoanthraquinoneacridone has been prepared by a new route; the various chloro derivatives of 6-aminoanthraquinoneacridone which have been synthesised are the 7-, 10-, and 11-monochloro, 7∶10-, 7∶11- and 10∶12-dichloro, the 7∶10∶12-trichloro and 11-chloro-7-bromo-compounds. It is found that the acridones containing a chlorine atom in the 7-position, adjacent to the amino group, are dehalogenated by treatment with aqueous alkali and hydrosulphite at room temparature (28°) for about one hour.

    • Anthraquinone and anthrone series - Part VII. A synthesis of islandicin

      B S Joshi B D Tilak K Venkataraman

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      The constitution (I), assigned by Howard and Raistrick1 to islandicin, the coloring matter from the dried mycelium ofPenicillium islandicum Sopp., has now been confirmed by unambiguous synthesis.

      3-Nitro-2-(5′-benzeneazo-2′-hydroxy-4′-methyl)-benzoylbenzoic acid (VII), obtained by coupling 3-nitro-2-(2′-hydroxy-4′-methyl)-benzoylbenzoic acid (VI) with diazotized aniline, gave on reduction 3-amino-2-(5′-amino-2′-hydroxy-4′-methyl)-benzoylbenzoic acid (VIII). The latter was converted in one step to 1∶4∶5-trihydroxy-2-methylanthraquinone (I) by tetrazotization and treatment with hot sulphuric acid. The properties of (I), its triacetate and its trimethyl ether are identical with those of islandicin, its triacetate and its trimethyl ether described by Howard and Raistrick.

    • Anthraquinone and anthrone series - Part VIII. 4-halogenoalizarins and their derivatives

      B S Joshi B D Tilak K Venkataraman

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      The synthesis of 4-chloro-, bromo- and iodo- alizarins is described. Bromination of 2-O-p-toluene sulphonylalizarin (I) in glacial acetic acid gave a monobromo derivative (II), which on hydrolysis yielded a new bromoalizarin (III). Methylation of (III) gave the known 4-bromoalizarin-2-methyl ether, showing that (III) is 4-bromoalizarin. Chlorination of (I) with sulphuryl chloride in nitrobenzene gave 4-chloro-2-O-p-toluene-sulphonylalizarin (XII), which on hydrolysis yielded 4-chloroalizarin. Condensation of (II) and (XII) with aniline andp-toluidine led to 4-anilino-and 4-p-toluidinoalizarins. In addition to the 4-arylaminoalizarins, 1:2:4-trianilino and 1:2:4-tri-p-toluidinoanthraquinones were isolated by chromatography. Condensation of 4-nitroalizarin with aniline in presence of boric acid gave 4-anilinoalizarin, which was different from the product described by Gonsalves,et al., as 4-anilinoalizarin. 6:7-Dihydroxyanthraquinoneacridone was prepared from (II) in the usual manner and examined as a vat dye. 4-Iodoalizarin-2-methyl ether (XV) was prepared from alizarin-2-methyl ether by nitration, reduction, and replacement of the amino group by iodinevia the diazonium salt. Demethylation of (XV) with aluminium chloride gave 4-iodoalizarin.

    • Anthraquinone and anthrone series - Part XIV. 1-Amino-3-chloroanthraquinone

      B S Joshi N Parkash K Venkataraman

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      1:3-Dichloroanthraquinone has been prepared by the deamination of 1-amino-2:4-dichloroanthraquinone. The dichloroanthraquinone is useful for the preparation of 1-amino-3-chloroanthraquinone.

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