Patent GB-573394-A (GB)
Title: Cyanine dyes with recurring cyanine nuclei and photographic silver halide emulsions sensitised therewith
IPC: C09B23/04
Filed: 1944-05-12
Abstract: Cyanine dyes are prepared by condensing a bis salt consisting of two 5- or 6-membered heterocyclic nitrogen nuclei linked together through their heterocyclic nitrogen atoms by a hydrocarbon linkage, the heterocyclic nitrogen nuclei each containing a reactive group in a or g  position to the heterocyclic nitrogen atom, with a 5- or 6-membered heterocyclic quaternary ammonium salt containing in a  or g  position to the quaternary nitrogen atom a group capable of reacting with the reactive groups.  The bis salt may contain thiazole, benzthiazole, oxazole, selenazole, iminazole, indolenine, dialkylindolenine, pyridine, or quinoline nuclei.  The reactive group may be a reactive methyl or methylene group; a halogen atom, e.g. iodine; alkylmercapto, e.g. methylmercapto or ethylmercapto; alkylselenomercapto; an acylmethylene group formed by the condensation of a reactive methyl group with an acyl halide, e.g. acetyl chloride, propionyl chloride, crotonyl chloride, or benzoyl chloride; a thione or selenone group; a nitrosamine group; a b -anilinovinyl group; an amino group; a hydrazone group; or a cyano group.  The second compound may contain one or more reactive groups. The reaction may be effected by mixing the reactants in the presence of a basic condensing agent in a solvent or diluent, or by refluxing together using a solvent and an acid binding agent or an acid binding solvent, e.g. an organic amine.  One mol. of ethylene-bis-a -methylbenzthiazole dibromide may be reacted with two mols. of a -methylmercaptoquinoline ethyl bromide, and one mol. of ethylene - bis - a  - methylmercaptoquinoline dibromide may be reacted with two mols. of a -methylbenzthiazole methyl bromide, in both cases in presence of an acid binding agent.  A polyheterocyclic quaternary salt having a reactive group may be condensed with itself or with a different polyheterocyclic quaternary salt having a reactive group, e.g. N : N1-ethylene-bis-(2-methylbenzthiazole) dibromide may be condensed with itself in presence of an acid binding agent such as pyridine, piperidine, dimethylamine or trimethylamine.  A polymeric pseudocyanine dye may be made by reacting one mol. of N : N1 - ethylene - bis - (2 - methylmercaptoquinoline) dibromide with one mol. of N : N1-ethylene-bis-(2-methylbenzthiazole) dibromide.  The nitrogen atoms of the heterocyclic nuclei may be linked by a saturated aliphatic hydrocarbon chain of up to 6 carbon atoms.  1 : 11-Ethylene-bis-(2-methylmercaptoquinolinium)-dibromide is prepared by heating together in a sealed tube 2-methylmercaptoquinoline and ethylene dibromide. Trimethylene-bis-(2-methylmercaptoquinolinium)-dibromide, tetramethylene-bis - (2 - methylmercaptoquinolinium) - dibromide, pentamethylene - bis - (2 - methylmercaptoquinolinium)-dibromide, hexamethylene-bis-(2-methylmercaptoquinolinium) - dibromide, and hexamethylene - bis - (2 : 5 - dimethylbenzelenazole) - dibromide are similarly prepared.  Bis-cyanine salts may also be prepared from the following bases containing reactive groups: a -picoline, g -picoline, 2 : 6-lutidine, 2 : 4-lutidine, 2 : 5-lutidine, 2 - methylbenzoxazole, 2 - methyl - b  - naphthoxazole, 2 - methylbenzselenazole, 2 - methyl - b  - naphthathiazole, 1 - methyl - a  - naphthathiazole, 2-methylthiazole, 2-methyloxazole, 2 : 6 - dimethyl - 5 - aminobenzthiazole, 2 : 4 - dimethyl-6-aminobenzthiazole, 2 : 4 : 6-trimethyl-7-aminobenzthiazole, 2-methyl-6-diethylaminobenzthiazole, 2-methyl-5-dimethylaminobenzthiazole, 2-methyl-6-acetylaminobenzthiazole, 2 : 4 : 6 - trimethyl - 7 - acetylaminobenzthiazole, 2 : 5-dimethyl-4-acetylthiazole, 2 : 5-dimethyl-4 - benzoylthiazole, 2 : 5 - dimethyl - 4 - thiazolecarboxyanilide, 2 - methyl - 4 - furylthiazole, 2-methyl-4-thienylthiazole, 2-methyl-5-ethoxybenzthiazole, 2 : 4 : 5 - trimethylbenzselenazole, 2 - methyl - 5 : 6 - dimethoxybenzthiazole, 2 - methyl - 5 - methoxyselenazole, 2 - methyl - 6 - ethoxybenzthiazole, 2-methyl-4 : 5-methylenedioxybenzthiazole, lepidine, 6 - methyllepidine, 1 : 3 : 3 - trimethyl - 2 - methylene - indoline, N-ethyl-2-methylene-dihydroquinoline, N-ethyl-6 : 7 - dimethyl - 2 - methylene-dihydroquinoline, N - methyl - 6 - chloro - 2 - methylenedihydroquinoline, 1 : 3 : 3 - trimethyl - 2 - methylene - naphthindole, 2 - methylthiazoline, 2 - methylselenazoline, 2 : 6 - dipropylpyridine, 2 - methyl - 6 - ethylpyridine, 2 : 4 : 6 - trimethylpyridine, 2 : 6 - dimethyl - 4 - phenylpyridine, and 2 : 6-dimethyl-4-benzylpyridine.  The polymethylene dibromides may be replaced by polyhalogen substituted alkanes, e.g. methylene dibromide, methylene dichloride, 1 : 2-propylene dibromide, butylene dichloride, ethylene and propylene di-iodides, isobutyl dibromide, tri - iodo - triethylmethane, 1 : 1 - dibromoethane, bromoform, acetylene tetrabromide, hexabromoethane, benzylidine dichloride, o  : o 1-xylylene dibromide, o  : o 1-xylylene dichloride, cyclohexane-1 : 2-, 1 : 3- and 1 : 4 - dibromides, and 1 : 3 - dibromo - 2 - hydroxypropane; alkyl esters of alkylene and cycloalkylene sulphonic acids, e.g. methanedisulphonic dimethyl ester, ethane-a  : b -disulphonic diethyl ester, ethane-a  : a -disulphonic dimethyl ester, a  : b -propanedisulphonic diethyl and dimethyl esters, b -methylpropane-a  : b -disulphonic dimethyl ester, the diethyl esters of n-hexane-, n-heptane-, and n-octane-disulphonic acids, methanetrisulphonic triethyl ester, ethane-a  : a  : b -trisulphonic triethyl ester, and propane - a  : b  : g  - trisulphonic triethyl ester; alkyl esters of arylenesulphonic acids, e.g. the diethyl ester of phenyldisulphonic acid, the dimethyl esters of naphthalene and diphenyl disulphonic acids, and the triethyl ester of phenyltrisulphonic acid; alkyl disulphates, e.g. dimethyl and diethyl-a  : b -ethanedisulphate; esters of sulphonic acids with polyhydric alcohols, e.g. alkyl, cycloalkyl, and aryl sulphonic acid esters with glycerol and the glycols, including ethylene - di - (ethylsulphonate), ethylene - di - (p - toluenesulphonate), ethylene - di - (cyclohexylsulphonate), p - phenylene - di - (p - toluenesulphonate), propylene - di - (p - toluenesulphonate) and hexamethylene-di-(p-toluenesulphonate); and mixed compounds, e.g. a -bromoethane-b -ethylsulphonate.  The hydrocarbon linking radicle may be substituted by non-quaternary salt-forming groups, e.g. nitro; primary, secondary and tertiary amino groups; hydroxy; carbonyl; thiocarbonyl; heterocyclic; and hydrocarbon groups.  11 : 111-Ethylene-bis-(3-ethyl-5-methylselenapseudocyanine) -dibromide is prepared by refluxing together in absolute alcohol N : N1-ethylene-bis - (2 - methylmercaptoquinolinium) - dibromide and 2 : 5-dimethylbenzselenazole ethyl bromide. 11 : 111-Trimethylene-bis-(3-ethyl-5-methylselenapseudocyanine) - dibromide, 11 : 111 - tetramethylene-bis-(3-ethyl-5-methylselenapseudocyanine) -dibromide, 11 : 111-pentamethylene-bis-(3-ethyl-5-methylselenapseudocyanine) - dibromide, 11 : 111-hexamethylene-bis-(3-ethyl-5-methylselenapseudocyanine) -dibromide, 3 : 31-hexamethylene-bis-(5-methyl-111 -ethylselenapseudocyanine)-dibromide, and polymeric 11 : 111-hexamethylene-bis-(3 : 3111-hexamethylene - bis - (thiapseudocyanine) - polybromide are similarly prepared.  2 : 5-Dimethyl-4-acetylthiazole is prepared by adding a carbon disulphide solution of bromine to a carbon disulphide solution of acetylacetone, pouring into ice-water, extracting with ether, and drying, adding a solution of thioacetamide in absolute alcohol and heating, pouring into water, making alkaline, extracting with ether, drying, and evaporating the ether.  2 : 5 - Dimethyl - 4 - benzoylthiazole is similarly prepared from benzoylacetone.  2 : 5-Dimethyl-4-thiazolecarboxyanilide is prepared by boiling together a -bromoacetoacetanilide and thioacetamide in alcohol. 2-Methyl-4-furylthiazole is prepared by adding a carbon disulphide solution of bromine to a carbon disulphide solution of methyl furyl ketone, and then reacting the product with thioacetamide. 2-Methyl-5-ethoxybenzthiazole is prepared by reducing 2 : 21-dinitro-4 : 41-diethoxydiphenyldisulphide in acetic anhydride with zinc dust.  2 : 21 - Dinitro - 4 : 41 - diethoxydiphenyldisulphide is prepared by refluxing together 3-nitro-4-chlorethoxybenzene, alcohol, sodium sulphide, sulphur and water.  2 : 5 : 6-Trimethylbenzselenazole is prepared by reducing 2 : 21-dinitro-4 : 5 : 41 - 51-tetramethyldiphenyldiselenide with zinc and acetic acid. 2 : 21-Dinitro-4 : 5 : 41 : 51-tetramethyldiphenyldiselenide is prepared by treating 2-nitro-4 : 5-dimethylchlorbenzene with sodium polyselenide.  a -Methylnaphthindole is prepared by treating the reaction product of naphthylhydrazine and acetone with zinc chloride. 1 - 3 : 3 - Trimethyl - 2 - methylenenaphthindolenine is prepared by methylating a -methylnaphthindole with methyl iodide and treating the product with caustic soda.  2 : 6-Dimethyl-4-benzylpyridine is prepared from two molecular proportions of ethyl acetoacetate and one molecular proportion each of ammonia, and phenylacetaldehyde by the method of Hantsch.  The dyes may be used as sensitizers for photographic silver halide emulsions, e.g. silver chloride, bromide, chlorobromide, bromiodide and chlorobromoiodide emulsions, and for mixed emulsions, e.g. mixtures of 25-75 per cent silver chloride with 75-25 per cent silver chlorobromide to one or both of which the dyes may be added prior to mixing.  The dyes may be dispersed in the emulsion prior to coating, or the coated emulsion may be bathed in a solution of the dye.  The dyes are particularly useful in elements having two emulsion layers of markedly different gradations selectively sensitized to different spectral regions.  The dyes may be used in the preparation of bleach-out, filter, anti-abrasion and anti-halation layers, and as binding agents for light-sensitive emulsions.  Hardening agents, desensitizers, wetting agents, anti-fogging agents, and other