Patent GB-487051-A (GB)
Title: Improvements in or relating to dyestuffs
IPC: C09B23/04
Filed: 1936-11-14
Abstract: Dyestuffs containing in the molecule a number of heterocyclic nitrogen nuclei linked together by methine or substituted methine groups or by nitrogen atoms or by chains of methine groups which may or may not include nitrogen atoms are made by treating a compound of the type (A) <FORM:0487051/IV/1> <FORM:0487051/IV/2> [where D = the remainder of a heterocyclic system, R = alkyl, aryl or aralkyl, R1 = alkyl and Y = the remainder of a 5-membered ring] with an alkyl salt, R1X to form a compound of the type (B) <FORM:0487051/IV/3> <FORM:0487051/IV/4> and then reacting with one of the following compounds: quaternary salts of heterocyclic nitrogen compounds having a reactive CH3 or external = CH2 group in the a - or g -position to the N atom; heterocyclic nitrogen compounds and their quaternary salts having a reactive NH2 or = NH group in the a  or g  position to the N atom; 5-membered ring compounds containing a ketomethylene group, e.g. rhodanic acid and similar compounds as described in Specification 426,718, thioindoxyls, coumaranones and indanedione; esters of the type R1OOC-(CH = CX)n-CH2-COOR1 [X = H or a monovalent group, R1 = alkyl and n = 0 or 1], e.g. malonic or glutaconic esters, or with one of the following condensing agents: acids of the type HOOC-(CH = CX)n-CH2COOH [X = H or a monovalent substituent, n = 0 or 1] such as malonic and glutaconic acids; anhydrides of acids of the general formula: CH3-(CX)2n-1 = CH-COOH (X = H or a monovalent group and n = 1 or 2) such as crotonic or substituted crotonic anhydrides; carbocyclic compounds containing a reactive cyclomethylene group such as cyclopentadiene and its homologues, e.g. indene; ammonia; amidines; hydrazines, and diamines, e.g. p-phenylene diamine.  The compound of the type A, an alkyl salt and a heterocyclic nitrogen base containing a reactive group as above defined or a cyclopentadiene or indene compound may also be fused together and the reaction completed if necessary by further boiling in a solvent. Compounds of the type A may be made according to Specification 485,110.  Examples of the 5-membered ring compounds are N-alkyl-, aryl- or aralkylderivatives of rhodanic acid, 2-seleno-4-keto-tetrahydrothiazole, 2 - thio(or seleno) - 4 - ketotetrahydrooxazole, or 2-thio-(or seleno) - 4 - ketotetrahydroselenazole.  Heterocyclic compounds which may be employed either in the first or final condensation may be those azoles, azines, diazoles and diazines &c. commonly used in making cyanine dyes.  Many of the products act as sensitizers for photographic silver halide emulsions.  According to examples: (1) 1-methylbenzthiazole methyl - p - toluene sulphonate is condensed with N-methyl-rhodanic acid in presence of acetic anhydride and pyridine and the dyestuff (A) fused with 1-methylbenzthiazole and ethyl-p-toluene sulphonate, then refluxed with pyridine, and the dyestuff precipitated with potassium bromide; further similar examples are given of dyes of type A from the following additional components viz. quaternary salts of 1-methylbenzoxazole, quinaldine, 2 : 3 : 3-trimethyl indolenine or lepidine and N-methyl- or ethyl-2-thio-4-ketotetrahydrooxazole or N-ethylrhodanic acid condensed with methyl- or ethyl-p-toluene sulphonate and 1-methylbenzoxazole, quinaldine or lepidine; (2) the product from 1-methylbenzthiazole ethiodide and N-methylrhodanic acid (type A) is fused with methyl-p-toluene sulphonate and the compound (type B) warmed with malonic or glutaconic acid and pyridine; similar dyes are obtained by using other compounds of type A made from components indicated in (1); (3) the compound from 1-methylbenzthiazole, methyl-p-toluene sulphonate, acetic anhydride and N-methylrhodanic acid (type A) is fused with methyl-p-toluene sulphonate and the product (B) refluxed with hydrazine hydrochloride in pyridine; (4) the compound of type A in (3) is fused with ethyl-p-toluene sulphonate and the product refluxed with thiohydantoin in pyridine; the compound from quinaldine, methyl-p-toluene sulphonate and N-methyl-rhodanic acid may also be used as starting material; (5) the product (type B) of (3) is boiled with N-methylrhodanic acid in pyridine; other starting materials of type A indicated in (1) may be similarly condensed; N-ethylrhodanic acid may also be used; (6) the product from 1-methylbenzoxazole, methyl-p-toluene sulphonate, acetic anhydride and N-ethylrhodanic acid (type A) is fused with methyl-p-toluene sulphonate and the mixture refluxed with 1 - phenyl - 3 - methyl - 5 - pyrazolone in pyridine; (7) and (8) the product type B of (3) is heated with cyclopentadiene or indene in pyridine; other products of type B from components mentioned in (1) may be similarly condensed; (9) and (10) the product from 1-methylbenzthiazole, methyl-p-toluene sulphonate (or 1-methyl benzthiazole methiodide), acetic anhydride and N-ethyl-(or methyl)-rhodanic acid is fused with ethyl-p-toluene sulphonate and 1-aminobenzthiazole, then refluxed with pyridine and the dyestuff precipitated with potassium iodide.