GB633487A - New thioindigoid dyestuffs - Google Patents

Abstract

4.7-Dichloro-, 7-chloro-, and 7-nitro-2.1-naphthisatins are made by the Sandmeyer chloral oxime synthesis from the corresponding 2 - naphthylamines. Specifications 610,117, 619,357, [Group IV (c)], 633,481 and 633,513 are referred to.ALSO:Leuco-sulphuric esters of naphthathionindigoid dyes of the formula <FORM:0633487/IV (c)/1> (where one of the hydrogen atoms in naphthalene nucleus A may be replaced by chlorine, and where X and Y may be hydrogen or chlorine or where one of X and Y is nitro, the other being hydrogen) are made from the dye in presence of a metal, or from the leuco-compound or metal salt thereof or complex compound comprising the metal salt thereof, by treating with a sulphating agent such as sulphur trioxide, in presence of a tertiary base or an organic amide in which the hydrogen atoms attached to the nitrogen atom have been replaced by hydrocarbon or substituted hydrocarbon radicles. In examples: (1) the unsubstituted dyestuff of the above formula; (2) the 4.7-dichloro-body; (3) the 7-chloro-body, and (4) the 7-nitro body are each reacted with copper powder and sodium pyrosulphate in pyridine; also in examples, the 4.7-dichloro-body is (5) reacted with zinc dust in pyridine in presence of tetraethylammonium chloride and then with sulphur trioxide-triethylamine, or (6) reacted with zinc dust in dimethylformamide in presence of sodium-b -naphthalene sulphonate, and then with dimethylformamide-sulphur trioxide. An alternative amide specified is N : N-diethyl-p-toluenesulphonamide. The naphthathioindigoid dyes of the above formula are made from the corresponding naphthisatin chloride and naphthathioindoxyl. Specifications 610,117, 619,357, 633,481 and 633,513 are referred to.