Patent GB-373601-A (GB)
Title: The manufacture of new hydroxy-thionaphthenes of the naphthalene series and of dyestuffs derived therefrom
IPC: C09B7/00
Filed: 1931-02-17
Abstract: Hydroxythionaphthenes of the naphthalene series are manufactured by converting a dialkoxy- or halogenalkoxy-naphthalenemonosulphonic acid into the corresponding sulphochloride, reducing the latter, condensing the mercaptan formed with monochloracetic acid, converting the thioglycollic acid so obtained into its acid chloride and effecting ring-closure of the latter.  The dialkoxynaphthalenemonosulphonic acids are prepared by treating a dihydroxynaphthalenesulphonic acid with an alkylating agent in the presence of alkali.  The halogenalkoxynaphthalenemonosulphonic acids are prepared by replacing the amino-group of an aminonaphtholsulphonic acid by halogen by Sandmeyer's reaction and alkylating the hydroxy-group.  The hydroxythionaphthenes are converted into symmetrical thioindigos by oxidation, and into asymmetrical dyestuffs by condensing them with cyclic o-diketones or with a -derivatives thereof, or by converting them into the a -derivatives of the corresponding diketodihydrothionaphthenes and condensing these with compounds containing a reactive methylene group, such as indoxyls or other hydroxythionaphthenes. In examples: (1) the sodium salt of 2 : 8-dimethoxynaphthalene-6-sulphonic acid is treated with phosphorus pentachloride, the sulphochloride is reduced with zinc dust and sulphuric acid and the mercaptan condensed with monochloracetic acid to produce 2 : 8-dimethoxynaphthalene-6-thioglycollic acid, which is treated with phosphorus trichloride and the thioglycollic acid chloride is converted by means of aluminium chloride into 4 : 6-dimethoxynaphthalene-2 : 1-oxythiophene; (2) 2 : 5-dimethoxynaphthalene-7-thioglycollic acid is similarly prepared from the sodium salt of 2 : 5-dimethoxynaphthalene, 7-sulphonic acid, and converted into 4 : 7-dimethoxynaphthalene - 2:1 - oxythiophene; (3) the sodium salt of 2-chloro-5-methoxynaphthalene-7-sulphonic acid (obtained by diazotizing 2 - amino - 5 - naphthol - 7 - sulphonic acid, treating the product with cuprous chloride and treating the 2-chloro-5-oxynaphthalene-7-sulphonic acid with dimethyl sulphate and caustic soda) is converted into 2-chloro-5-methoxynaphthalene-7-thioglycollic acid and the latter into 7-chloro-4-methoxy-2 : 1-naphthoxythiophene; (4) 2-amino-a -naphthol-6-sulphonic acid, 2-amino-3-naphthol-6-sulphonic acid, and 1-amino-a -naphthol-4-sulphonic acid are similarly converted into the corresponding halogenalkoxynaphthalenesulphonic acids and these, via the thioglycollic acids, into the corresponding thionaphthenes; (5) 4 : 6 - dimethoxynaphthalene-2 : 1-oxythiophene is condensed with 5 : 7-dichlorisatin, producing a dyestuff which dyes cotton yellowish-brown shades, or with 5 : 7-dibromisatin to produce a similar dyestuff; (6) the same compound is condensed with 5-bromisatin chloride (obtained by the action of phosphorus pentachloride on 5-bromisatin); the product dyes cotton currant shades; (7) the same compound is condensed with 6 - chlorodiketodihydrothionaphthene - p-dimethylaminoanil (obtained by treating 6-chlorooxythionaphthene with nitrosodimethylaniline in the presence of caustic alkali); the product dyes and prints cotton bright reddish-brown shades; (8) 4 : 7-dimethoxynaphthalene-2 : 1-oxythiophene is condensed with 2 : 1-naphthodiketodihydrothiophenedimethylaminoanil (obtained by treating 2 : 1-naphthooxythiophene with nitrosodimethylaniline in the presence of caustic alkali); the product dyes cotton brown shades; (9) 6 - chloro-4-methoxy - 2 : 1-naphthoxythiophene is condensed with 2 : 1-naphthodiketodihydrothiopheneanil; the product dyes cotton reddish-brown; (10) 7-chloro-4-methoxy-2 : 1-naphthoxythiophene is condensed with 5 : 7-dichlorisatin chloride (prepared in situ from 5 : 7-dichlorisatin and phosphorus pentachloride); the product dyes cotton currant shades; (11) 6-chloro-4-methoxy-2 : 1-naphthoxythiophene is condensed with 5 : 7-di-chlorisatin; the product dyes cotton yellowish-brown shades.  Reference has been directed by the Comptroller to Specification 298,493, [Class 2 (iii), Dyes &c.].