Patent GB-431661-A (GB)
Title: The manufacture of indigoid vat dyestuffs
IPC: C09B7/00
Filed: 1934-06-08
Abstract: Thioindigoid vat dyestuffs are manufactured by condensing an alkoxydichlorohydroxythionaphthene, in which the alkoxy group is in the 5, 6 or 7 position and one o-position thereto is free, with an isatin of the benzene or naphthalene series or a reactive 2-derivative thereof or with a reactive 2-derivative of a hydroxythionaphthene of the benzene or naphthalene series, or by condensing a reactive 2-derivative of the said alkoxydichlorohydroxythionaphthene with a hydroxythionaphthene of the benzene or naphthalene series.  Some of the products may be improved by after - halogenation.  In examples: (1) 5 - methoxy - 6 : 7 - dichloro-3-hydroxythionaphthene is condensed with 9-chloro-1 : 2-naphthisatin; the product dyes cotton grey shades; (2) 5-bromisatin is converted into its chloride by means of phosphorus pentachloride and condensed with 5-methoxy-4 : 7 - dichloro - 3 - hydroxythionaphthene; the product dyes cotton navy blue shades; (3) 6-ethoxy-4 : 7-dichloro-3-hydroxythionaphthene is condensed with 6-methoxy-2 : 3-diketodidihydrothionaphthene-2-(p-dimethylaminoanil) (obtainable by reacting 6-methoxy-3-hydroxythionaphthene with nitrosodimethylaniline); the product dyes cotton orange shades; (4) 5-methoxy-6 : 7-dichloro-2 : 3-diketodihydrothionaphthene - p - dimethylaminoanil (obtained by reacting 5 - methoxy - 6 : 7 - dichloro-3-hydroxythionaphthene with nitrosodimethylaniline) is condensed with 2 : 1-naphthoxythiophene; the product dyes cotton brown shades; (5) 5 : 7-dichlorisatin is converted by means of p phosphorus pentachloride into its chloride, which is condensed with 7 - methoxy - 4 : 5 - dichloro - 3-hydroxythionaphthene; the product dyes cotton blue shades.  A table gives the properties of further dyestuffs, the following additional second components being specified: 5 : 7-dibromisatin chloride, 4 - methyl - 5 - chloro - 7-methoxyisatin chloride, 4-methyl-6-chloro-3-hydroxythionaphthene-anil, 6-ethoxy-3-hydroxythionaphthene-anil and 3-hydroxythionaphthene-anil. Specification 222,094, [Class 2 (iii)], is referred to.  The Specification as open to inspection under Sect. 91 contains also a reference in the table to the use of 8-chloro-1 : 2-naphthisatin chloride.  This subject-matter does not appear in the Specification as accepted.  The alkoxydichlorohydroxythionaphthenes employed as starting materials are manufactured by converting the corresponding alkoxydichlorobenzenesulphonic acids by way of the sulphochlorides and mercaptans into the thioglycollic acids and effecting ring closure thereof, or by introducing a sulphur-containing radicle into the o-position to the amino group of a corresponding alkoxydichloroaminobenzene.  In examples: (1) 5-methoxy-6 : 7-dichloro-3-hydroxythionaphthene is prepared by acting with phosphorus pentachloride on the sodium salt of 2 : 3 - dichloranisole - 4 - sulphonic acid (obtainable by sulphonation and alkylation of 2 : 3-dichlorophenol), or with chlorosulphonic acid on 2 : 3-dichloranisole, reducing the resulting sulphochloride to the mercaptan, converting this by means of chloracetic acid into the thioglycollic acid and effecting ring closure; (2) 5 - methoxy - 4 : 7 - dichloro - 3 - hydroxythionaphthene is similarly prepared from the sodium salt of 2 : 5-dichloramisole-4-sulphonic acid obtainable from 2 : 5-dichlorophenol as in (1); (3) 6-ethoxy-4 : 7-dichloro-3-hydroxythionaphthene is prepared from 2 : 5-dichloro-4-ethoxyaniline hydrochloride by way of the sulphur chloride compound, 1-amino-2 : 5-dichloro-4-ethoxybenzene - 6 - thioglycollic acid, the cyanogen compound and the aminothionaphthenecarboxylic acid; (5) 7-methoxy-4 : 5-dichloro-3-hydroxythionaphthene is produced from 3 : 4 - dichloranisole - 6 - sulphonic acid (obtainable by sulphonation and alkylation of 3 : 4-dichlorophenol) by a method analogous to that of (1).