GB231567A - Manufacture of blue vat-dyestuffs - Google Patents

Abstract

Thioindigoid dyes are produced by halogenating the 2 : 3 : 21 : 31-bis-naphthothiophene-indigo or the dyestuffs made by condensing 2 : 3-naphthoxythiophene with reactive a -derivatives of isatin; or, similar products are obtained by condensing suitable components one or both of which contain halogen, that is, by condensing (a) halogenated 2 : 3-naphthoxythiophenes with nonhalogenated isatins or 2 : 3-naphthioisatins having reactive a -substituents, (b) non-halogenated 2 : 3-naphthoxythiophenes with nuclear halogenated isatins, or 2 : 3-naphthioisatins having reactive a -substituents, (c) halogenated 2 : 3-naphthoxythiophenes with nuclear halogenated isatins or 2 : 3-naphthioisatins having reactive a -substituents. The halogenated 2 : 3 : 21 : 31-bis-naphthothiophene-indigos may also be made from halogenated 2 : 3-aminonaphthoic acids; when starting with the 1-halogen compound, for instance the 1-chloro-compound, it is first converted into 1 : 2-dichloro-3-naphthoic acid by Sandmeyer's reaction, condensed with thioglycollic acid, and the 1-chlornaphthalene-2-thioglycollic-3-carboxylic acid converted by the usual methods to the corresponding oxythionaphthene which is then oxidized to the dyestuff; an example is given in which the ring closure is effected with acetic anhydride. The products dye cotton from the vat in indigo-blue shades fast to chlorine, kier-boiling, and light; they may also be printed on cotton. The condensation of a halogenated 2 : 3-naphthoxythiophene with an a -anil or an a -halide of 2 : 3-thionaphthisatin, and the halogenation of 2 : 3 : 21 : 31-bis-naphthothiophene-indigo or of 2 : 3-naphthothiophene-2-indol-indigo when prepared by the method claimed in Specification 219,280 are excluded. According to examples (1) 2 : 3-naphthioindigo is brominated in nitrobenzene or sulphuric acid, and chlorinated to a dichlor derivative in sulphuric acid in presence of iodine, or to a monochlor derivative by means of sulphuryl chloride in chlorobenzene; (2) 2 : 3-naphthoxythiophene is condensed with 5 : 7-dibromisatin-a -chloride and the product further brominated or chlorinated; (3) 1-brom-2(S)-3-(CO)-naphthoxythiophene is condensed with 5 : 7-dibrom-or 5 : 7-dichlorisatin-a -chloride; (4) the dyestuff from 2 : 3-naphthoxythiophene and isatin-a -chloride is brominated. 1-Halogen-2 : 3-aminonaphthoic acids are obtained by acetylating 2 : 3-aminonaphthoic acid, halogenating, and saponifying; chlorination by means of hydrochloric acid and sodium chlorate is described. Halogen-2 : 3-naphthioisatins may be prepared from halogen-2 : 3-naphthoxythiophenes by the methods described in Specification 28240/06.