Patent GB-759601-A (GB)
Title: Improvements in the manufacture of cyanine and merocyanine dyes
Inventor: LARIVE HENRI
IPC: A47L13/146
Filed: 1953-06-17
Abstract: Compounds of the general formula <FORM:0759601/IV(a)/1> wherein R is an alkyl group, Y is an anion and Z completes a benzthiazole or naphthathiazole nucleus are prepared by heating a compound of the formula <FORM:0759601/IV(a)/2> where M is an alkali metal, with an alkyl salt RY.  The alkali metal sulphonates may be prepared by oxidizing the corresponding mercapto compounds with hydrogen peroxide or sodium hypochlorite in an alkaline aqueous solution as is described in Specifications 416,291 and 445,581, preferably at 20-30 DEG  C.  Alternatively the alkali metal sulphonates may be prepared by mixing the corresponding halogen compounds with an aqueous solution of an alkali metal sulphite.  Examples are given of the heating of sodium benzthiazole-2-sulphonate and sodium a -naphthathiazole-2-sulphonate with dimethyl sulphate.  The sodium a -naphthathiazole-2-sulphonate is prepared by adding sodium hypochlorite solution to a caustic soda solution of 2-mercapto-a -naphthathiazole cooled in ice.  2-Mercapto-a -naphthathiazole is prepared by heating b -naphthylamine, CS2 and sulphur in a bomb at 210 DEG  C.  Compounds of the general formula <FORM:0759601/IV(a)/3> wherein X is an anion and D1 completes a benzthiazole, benzselenazole or naphthathiazole nucleus are prepared by mixing a methyl salt CH3X with a methylene base of the formula <FORM:0759601/IV(a)/4> Examples are given of the addition of methyl iodide to bases of the above formula wherein D1 has each of the values specified above.ALSO:Cyanine and merocyanine dyes are prepared by condensing a compound of the general formula:- <FORM:0759601/IV(c)/1> wherein R is an alkyl group, Y is an anion and Z completes a nucleus of the benzthiazole or naphthathiazole series, with a compound having one of the general formulae: <FORM:0759601/IV(c)/2> <FORM:0759601/IV(c)/3> (the latter compound giving a trinuclear dye) wherein R1 is an alkyl group, X is an anion, n is 1 or 2, Q and Q1 complete 5 - or 6 - membered heterocyclic nuclei and D1 completes a nucleus of the benzthiazole, benzselenazole or naphthathiazole series.  The condensations are preferably carried out in the presence of a basic condensing agent and by refluxing in a solvent such as a carboxylic anhydride, dioxane, piperidine, acetic acid, formamide, nitromethane, nitrobenzene, cresol, alcohols or even water.  Lists of nuclei which Q and Q1 may complete are given, including 41 - (2 - thienyl thiazole), thionaphtheno - 71, 61, 4, 5 - thiazoles, and 1- and 3 - iso-quinolines for Q, and 3 - carboxymethyl-, 3 - carboxyethyl-, 3-sulphomethyl-3 - p-carboxyphenyl-, 3 - p - sulphophenyl- and 3 - (benzothiazyl-rhodanines, 2 - alkylamino - or 2 - diphenylamino - 4 - thiazolones, derivatives of 2 - thiohydantoin including 1 - carboxymethyl, 1 - sulphomethyl, 1 - p - carboxyphenyl and 1 - p - sulphophenyl derivatives, tetronic acid, coumarones, homophthalimide, succinimide, thionaphthenones, 1 - p - carboxyphenyl - 3 - methyl - 5 - pyrazolone, 3 - methyl - 1 - (4 - sulpho - 1 - naphthyl) - 5 - pyrazolone, dihydrocarbostyril, quinoxalones, 3 - phenomorpholones and 1, 4, 2 - benzothiazine - 3 - one for Q1.  Examples of all three types of condensations are given.  Specifications 416,291 and 445,581 are referred to.