US2689849A - Cyanine dyes containing the triazolo[4, 3-alpha] quinoline or tetrazolo[alpha] quinoline nucleus - Google Patents

Description

Patented Sept. 21, 1954 CYANINE DYES CONTAINING THE TRI- AZOLO[4,3-a]QUINOLINE OR TETRA- ZOLO [a] QUIN OLINE NUCLEUS Leslie G. S. Brooker, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application September 10, 1952, Serial No. 308,908

10 Claims. 1

The instant application relates to new cyanine dyes, useful in sensitizing photographic halide emulsions, and methods for making such dyes.

Certain dyes of the cyanine dye series are known to extend the sensitivity of photographic silver halide emulsions. Dyes which have been found useful for this urpose include those which contain a quinoline nucleus. Such dyes have been long known, although they have not been particularly eflicacious for such purposes as sensitizers for photographic emulsions. While dyes of the above mentioned type are classed as weak sensitizers, I have now found a new class of dyes,

some of which are especially useful in extending the sensitivity of photographic silver halide emulsions.

It is an object of the present invention to provide new dyes of the cyanine series and to provide a process for preparing such dyes. A further object is to provide photographic silver halide emulsions sensitized with such dyes. A still further object is to provide a process for preparing photographic silver halide emulsions containing these new dyes. Other objects will become apparent hereinafter.

Thenew dyes of the cyanine series of my invention can be represented by the following general formula:

wherein R and. R1 each represents an alkyl group, such as methyl, ethyl, n-propyl, isopropy1,n-butyl, benzyl (phenylmethyl) etc., D represents the non-metallic atoms necessary to complete a carbocyclic nucleus of the benzene series, X represents an acid radical, such as chloride, bromide, iodide, perchlorate, thiocyanate, benzenesulfonate, p-toluenesulfonate, ethylsulfate, methylsulfate, etc., Q represents a nitrogen atom or a methine group, d and n each represents a positive integer of from 1 to 2, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from five to six atoms in the heterocyclic ring, such as those selected from the group consisting of those of the thiazole series (e. g. thiazole, i-methylthiazole, i-phenylthiazole, 5-methylthiazole, 5-pheny1thiazole, 4,5-dimethy1thiazole, 4,5-dipheny1thiazole,

thiazole series (e. g. benzothiazole, 4-chloroben zothiazole, 5-chlorobenzothiazole, fi-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, 5-methy1benzothiazole, fi-methylbenzothiazole, 5-bromobenzothiazole, G-bromobenzothiazole, 4e-phenylbenzothiazole, B-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzothiazole, G-methoxybenzothiazole, 5-iodobenzothiazole, fi-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.) those of the naphthothiazole series (e. g. a-naphthothiazole, fl-naphthothiazole, 5-methoxy ,3 naphthothiazole, 5-ethoxy-p-naphthothiazole, s-methoxy-anaphthothiazole, 7-methoxy-u-naphthothiazole, etc.), those of the thianaphtheno-Z',6,4,5-thiazole series (e. g. 4-methoxythianaphtheno 7,6,4,5-thiazole, etc.), those of the oxazole series (e. g. l-methyloxazole, 5-methyloxazole, l-phenyloxazole, 4,5-diphenyloxazole, 4-et-hyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, etc.), those of the benzoxazole series (e. g. benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5- phenylbenzoxazole, G-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5- methoxybenzoxazole, 5-ethoxybenzoxazole, 5- chlorobenzoxazole, G-methoxybenzoxazole, 5-hydroxybenzoxazole, G-hydroxybenzoxazole, etc.), those of the naphthoxazole series (e. g. a-naphthoxazole, B-naphthoxazole, etc.), those of the selenazole series (e. g. 4-methylselenazole, 4-phenylselenazole, etc.), those of the benz oselenazole series (e. g. benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.) those of the naphthoselenazole series (e. g. a-naphthoselenazole, ,Li-naphthoselenazole, etc.), those of the thiazoline series (e. g. thiazoline, l-methylthiazoline, etc.) those of the 2-quinoline series (e. g. quinoline, 3-methylquinoline, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, G-chloroquinoline, 8-ch1oroquinoline, 6- methoxyquinoline, d-ethoxyquinoline, B-hydroxyquinoline, 8-hydroxyquinoline, etc.) those of the 4-quinoline series (e. g. quinoline, G-methoxyquinoline, 7-methylquinoline, 8-methy1quinoline, etc.), those of the l-isoquinoline series (e. g. isoquinoline, 3,4-dihydroisoquinoline, etc.) those of the 3-isoquinoline series (e. g. isoquinoline, etc.), those of the 3,3-dialkylindolenine series (e. g. 3,3-dimethy1indolenine, 3,3,5-trimethylindolenine, 3,3,T-trimethylindolenine, etc.), the pyridine 4-(Z-thienyDthiazole, etc.), those of the benzoseries (e. g. pyridine, 5-methylpyridine, etc.), etc.

The cyanine dyes represented by Formula I above (d is 1) can advantageously be prepared by condensing a cyclammonium quaternary salt selected from those represented by the following wherein R, D, Q and X eachhave the values set forth above, together with a cyclammonium quaternary salt selected from those represented by the following general formula:

III

wherein R1, n, and Z each have the values given above, X1 represents an acid radical, e. g. chloride, bromide, iodide, perchlorate, thiocyanate, benzenesulfonate, p-toluenesulfonate, ethylsulfate, methylsulfate, etc., and R2 represents an alkyl group, e. g. methyl, ethyl, etc., or an aryl group, e. g. phenyl, tolyl (o-, m-, and p-), etc. The condensations can advantageously be carried out in the presence of a basic condensing agent, e. g. the organic tertiary amines, such as triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, etc., N-methylpiperidine, N-ethylpiperidine, N,N-dimethylaniline, N',N-diethylaniline, etc. The condensations can advantageously be effected in the presence of an inert solvent, e, g. ethanol, isopropanol, 1,4-dioxane, etc. Heating accelerates the condensations and temperatures varying from room temperature (about 20 C.) to the temperature of the steam bath can be used.

The cyclammonium quaternary salts selected from those represented by Formula II above can advantageously be prepared by heating the corresponding free base together with an alkyl salt, e.,g.

wherein R and .X each have the values given above. The free bases can be prepared in accordance with the method described by Marckwald et al. in Berichte (1900), volume 33, pages 18854899. Quaternization can be effected by simply heating the free base together with the alkyl salt on an oil bath or a steam bath until the mass sets to a solid (generally -20 hours). The cyclamrnonium quaternary salts can have substituents on the oarbocyclic ring, such as halogen (e. g. chlorine, bromine, etc.), hydroxyl, alkoxyl, etc.

The carbocyanine dyes represented by Formula I above (at is 2) can advantageously be prepared by condensing a cyclammonium quaternary salt selected from those represented by the following general formula:

wherein R1,,X1, n, and Z each have the values given above, R3 represents an acyl group (e. g. acetyl, propionyl, benzoyl, etc.), and R4 represents an aromatic group (e. g. phenyl, tolyl, naphthyl, etc), together with a cyclammom'um quaternary salt selected from those represented by Formula II above. The condensations can advantageously be effected'in the presence of a basic condensing agent, such as those set forth above for the condensation of the compounds of Formula II with those of Formula III. Likewise, the condensations can advantageously be effected in the presence of an inert solvent, such as those set forth above for the condensation of the compounds of Formula II with those of Formula III. Heating accelerates the condensations and temperatures varying from room temperature (about 20 C.) to the temperature of the steam bath can be used. The following examples will serve to illustrate more fully the manner whereby I practice my invention.

Example 1.1,3-diethyl-5-s-triazolo[4,3-a]- mine-.2 -cyam'ne perchlorate 0.8? gram (1 mol.) of 5-methyl-3-triazolo- [Mi-alquinoline and 1.50 grams (1 mol.+50% excess) of ethyl p-toluenesulfonate were heated together on an oil bath at C. for 15 hours. After cooling the fused mass to room temperature, 1.97 grams (1 mol.) of Z-phenylmercaptoquinoline ethiodide, 1.11 grams (2 mols.+5% excess) of triethylamine and 13 cc. of pyridine were thenadded and the resulting mixture refluxed 25 minutes. After recipitating the dye with an excess of aqueous potassium perchlorate, it was chilled, filtered oif, washed well with hot water and acetone and crystallized twice from methyl alcohol; cc./ gram) The final yield was 13% of the theoretical. The maroon crystals melted at 21'7-2 l8 C. dec.

Example 2.-3,3'-cliethylthia-5'-s triazolo- [4,3-al quinocyam'ne perchlorate 0.87 gram (1 mol.) of 5-methyl-s-triazolo- [4,3-alquinoline and 1.50 grams (1 mol.+50% excess) of ethyl p-toluenesulfonate were heated together on an oil bath at 140 C'. for 15 hours. After cooling the fused mass to room temperature, 2.00 grams (1 :mol.) of Z-phenylmercaptobenzothiazoleethiodide, 1.11 grams (2 mols.+.5% excess) of triethylamine and 15 cc. of pyridine were then added and the resulting mixture refiuxed 25 minutes. After precipitating the dye with an excess of aqueouspotassium perchlorate, it was chilled, filtered off, washed with hot water and acetone and crystallized twice from methyl alcohol; (340 cc./gram). The final yield was 15% of the theoretical. The felt-like mass of orange crystalsmelted at 255-257 C. dec.

Example 3.-3,3-diethylthia-5'-s-triazolo- [4,3-11]quinocarbocyanine perchlorate 0.8? gram (1 mol.) of 5-methyl-s-triazolo [4,3-alquinoline and 1.50 grams (1 mol.+50% excess) of ethyl p-toluenesulfonate were heated together on an oil bath at 140 C. for hours. After cooling the fused mass to room temperature, 2.25 grams '(1 mol.) of Z-B-acetanilidovinylbenzothiazole ethiodide, 1.11 grams (2 mols.+5% excess) of triethylamine and 15 cc. of pyridine were then added and the resulting mixture refiuxed for 30 minutes. After precipitating the dye with an excess of aqueous potassium perchlorate, it was chilled, filtered off, washed well with hot water and acetone and crystallized twice from methyl alcohol; (330 cc./gram). The final yield was 8%. The purplish crystalline powder melted at 236-238 C. dec.

Example 4.-3,3-diethyZ-5-tetraaolo [a] quz'nothiacyam'ne iodide 0.92 gram (1 mol.) of 5-methyltetrazolaEalquinoline and 1.50 grams (1 mol+50% excess) of ethyl p-toluenesulfonate were heated together on an oil bath at 140 C. for 15 hours. After coolin the fused mass to room temperature, 2.00 grams (1 mol.) of 2phenylmercaptobenzothiazole ethiodide, 1.11 grams (2 mols.+5% excess) of triethylamine and 15 cc. of ethyl alcohol were then added and the resulting mixture refluxed 15 minutes and then chilled. The crude dye that separated was filtered off, washed with cold ethyl alcohol, water, acetone and then crystallized twice from methyl alcohol; (150 cc./gram). The final yield was 11% of the theoretical. The orange crystals melted at 245-24? C. dec.

Example 5.1 ',3-dz'ethyZ-5-tetrazolo[a] quz'no-T-cyam'ne iodide 0.92 gram (1 mol.) of 5-methyltetrazoloEalquinoline and 1.50 grams (1 mol.+50% excess) of ethyl ptoluenesulfonate were heated together on an oil bath at 140 C. for 15 hours. After cooling the fused mass to room temperature, 1.97 grams (1 mol.) of 2-phenylmercaptoquinoline ethiodide, 1.11 grams (2 mols.+5% excess) of triethylamine and 15 cc. of ethyl alcohol were then added and the resulting mixture refluxed 15 minutes and then chilled. The crude dye was filtered off, washed with cold ethyl alcohol, Water, acetone and then crystallized twice from methyl alcohol; (57 cc./gram). The final yield was 31% of the theoretical. The brilliant copper flakes melted at 244-246 C. dec.

Example 6.3,3-diethylo-xa-5-tetrazolo[al quinocarbocyanine iodide 0.92 gram (1 mol.) of 5-methyltetrazololalquinoline and 1.50 grams (1 mol.+50% excess) of ethyl p-toluenesulfonate were heated together on an oil bath at C. for 15 hours. After cooling the fused mass to room temperature, 2.1? grams (1 mol.) of 2-,8-acetanilidovinylbenzoxazole ethiodide, 1.11 grams (2 mols.+5% excess) of triethylamine and 15 cc. of ethyl alcohol were then added and the resulting mixture refluxed 15 minutes and then chilled. The crude dye that separated was filtered off, washed with cold ethyl alcohol, water, acetone and then crystallized twice from methyl alcohol; (59 (ad/gram). The final yield was 35% of theoretical. The bluish-green needles melted at 234-236 C. dec.

Example 7.3'-ethyZ-3-methyZ-5-tetrazololal qumothiacyanine p-toluenesulfonate 0.92 gram (1 mol.) of 5-methyltetrazolofalquinoline and 1 gram (1 mol.|7% excess) of methyl-p-toluenesulfonate were heated together for 20 hours on a steam bath. The melt was cooled and washed with ether. 1.75 grams (1 mol.) of 2-ethylmercaptcbenzothiazole ethoethylsulfate, 15 cc. of ethyl alcohol, and 1.1 grams (2 mo1s.+10% excess) of triethylamine were added to the crude quaternary salt, and the mixture was refluxed for 30 minutes. The reaction mixture was cooled and treated with ether. The residue was titurated with ethyl alcohol, and the dye was filtered off and washed with ethyl alcohol. After two recrystallizations from methyl alcohol (650 cc./gram) the yield was 5% of the theoretical. The orange crystals melted at 255-2=56 C. dec.

It has also been found that the intermediates represented by Formula 11 above can be condensed with a p-aminoaromatic aldehyde to produce dyes of the styryl class. Useful aldehydes include, for example, p-dimethylaminobenzaldehyde, p diethylaminobenzaldehyde, etc. The condensations are advantageously eifected in the presence of a basic condensing agent, e. g. piperidine, etc. The condensations can be carried out in the presence of an inert solvent, e. g., ethanol, propanol, isopropanol, n-butanol, etc. Heating accelerates the condensations and temperatures varying from room temperature (about 20 C.) to the temperature of the steam bath can be used. The styryl dyes thus obtained have been found to be particularly useful in the preparation of filter layers, overcoating layers, and the like in photographic elements.

The following examples will serve to illustrate the manner whereby styryl dyes can be prepared according to my invention.

7 Emample 8'.---5-. dimethylaminostyryl-3-ethyZ-striazolo [4,341] quinolinium iodide 1.73. grams (1 mol.) of -methyl-s-triazolo [4,3-a] quinoline and 4 grams (1 mol.+100% excess) of ethyl-p-toluenesulfonate were heated together for 20 hours on a steam bath. The'melt was cooled to room temperature and washed with ether. grams (1 mol.) of p-dimethylaminobenzaldehyde and 5 cc. of piperidine were added to the crudequaternary salt and themixture was refluxed for five minutes. The reaction mixture was cooled and extracted twice with ether. The residue was dissolved in ethyl alcohol and treated with an aqueous solution of sodium iodide. After cooling, the crystals were filtered off and-washed with ethyl alcohol. After two recrystallizations from methyl alcohol (100 cc./ gram) the yieldwas 17% of the theoretical. The reddish-brown crystals melted at 278-280 C. dec.

Example 9.5-p-dimethylaminostyryl 3 ethyltetrazolo [al quinolim'um iodide was 50% of the theoretical. The maroon needles melted at 259-261 C. dec.

As shown above I have found that my new cyanine dyes (Formula I) spectrally sensitize photographic silver halide emulsions'when-incorporated therein. The dyes are especially'useful for extending the spectral sensitivity-of the customarily employed gelatino-si1verchloride, gelatino-silver-chlorobromide, gelatino silver bromide and gelatinosilver-bromiodide developingout emulsions. To prepare emulsions sensitized with one or more of my new dyes, it is only necessary to disperse the dye or dyes-in the emulsions. The methods of incorporating dyes in emulsions are simple and are known to those skilled in the art. In practice, it is convenient to add the dyes to the emulsions in the form of a solution in an appropriate solvent. Methanol or acetone has proved satisfactory as a solvent for=most-of my new cyanine'dyes. Where the dyes arequiteinsoluble in methyl alcohol, a mixturenfacetone and pyridine isadvantageously employed as a solvent. The dyes are advantageously-incorporated in the finished, washed emulsions-wand should be uniformly distributed throughout the emulsions. The particular. solvent vused will, of

course, depend on the solubility properties of the particular dye.

The concentration of the dyes in the emulsions can vary widely, e. g. from 5 to mg. per liter of fiowable emulsion. The concentration of the dyes will vary according to the type of emulsion and according to the effect desired. The suitable andmost economical concentration for any given emulsion will be apparent to those skilled in the art, upon making the ordinary tests and observations customarily used in the art of emulsion making. To prepare a gelatino-silver-halide emulsion sensitized with one or more of my new dyes,- the following procedure is satisfactory.

A-quantity of dye is dissolved in methyl alcohol or acetone (or a mixture of acetone and pyridine) and a volume of this solution, which may be diluted with water, containing from 5 to 100 mg. of dye, is slowly added to about 1000 cc. of gelatinosilver-halide emulsion, with stirring. Stirring is continued until the dye is thoroughly dispersed in the emulsion.

With most of my dyes, from 10 to 20 mg. of dye per liter of gelatino-silver-bromide or bromoiodide emulsion (containing about 40 g. of silver halide) suffices to produce the maximum sensitizing effect. With the finer grain emulsions, somewhat larger concentrations of dye maybe needed to produce the maximumsensitizing effect.

The above statements are only illustrative, as it will be apparent that the dyes can be incorporated in photographic emulsions by any of the other methods customarily employed in the art, e. g. by bathing a, plate or film upon which an emulsion is coated in a solution of the dye in an appropriate solvent. However, bathing methods are ordinarily not to be preferred. Emulsions sensitized with the dyes canbe coated on suitable supports, such as glass, cellulose iderivativefilm, resin film or paper in the usual manner.

For the preparation of overcoating layers, filter layers, antihalation layers, etc., from the styryl dyes obtained according to my invention, from 50 mg. to mg. ofstyryl dye is'dissolved in from 2 to 5 cc. of water-miscible solvent. Methanol or acetone is suitable for this purpose, but pyridine or fi-ethoxyethanol can also be used. The solution is then added to about 25 cc. of a 5% gelatin solution at about40 C.:and .the mixture coated on the support.

It has also been found that a 2-alkylmercaptolepidine selected from those represented by the following general formula:

wherein R5 represents an alkyl group, e. g. methyl, ethyl, etc., can be heated with an alkyl salt (Rs-X2) to give a quaternary salt having the following general formula:

V (a) ?Ha wherein R has the values given above, ,Rc represents an alkyl group, e. g. methyl, ethyl, etc., and X2 represents anacid radical, e. g. chloride, bro- .mide, iodide p-toluenesulf.onate, etc.

The intermediates represented by Formula V (a) above can be condensed with a compound selected from those represented by Formula IV above to give a carbocyanine dye selected from those represented by the following general formula:

wherein R1, Ra, Ra, X2, n, and Z each have the values given above. been found useful for altering the sensitivity of photographic silver halide emulsions. The condensations can advantageously be effected in the presence of a basic condensing agent, e. g. triethylamine, tri-n-butylamine, etc.

dium selenide to produce un-ionized dyes represented by the following resonance structures:

wherein R1, R6, n and Z each have the values given above. The dyes represented by Formula VII above give colors in solution that are considerably deepened on adding a solution of silver nitrate, indicating the formation of the isomer represented as Formula VII (b) above. dyes are, accordingly, excellent indicators for the presence of the silver ion. Some of the new dyes represented by Formula VII are also useful in extending the sensitivity of photographic silver halide emulsions.

The following examples will serve to illustrate the manner whereby the new dyes represented by Formulas VI and VII can be prepared according to my invention.

Example 1 0.-1 ',3-dzethyl-2' -ethylmercapto-oma- 4-carbocyanine perchlorate (2 mols, excess) of triethylamine and 70 These dyes, likewise, have Inert sol-y vents can also be employed in the condensations,

Such

10 cc. of ethyl alcohol were refluxed for 12 minutes and the dye precipitated with an excess of aqueous potassium perchlorate. After chilling the reaction mixture, the dye was filtered oiI, washed with cold ethyl alcohol, hot water, acetone and crystallized twice from methyl alcohol; (500 cc./gram). The final yield was 25% of the theoretical. The minute green crystals melted at 251-253 C. dec.

Example 11.1,3-diethyl-Z'-ethylmereaptothia- 4-carbocyanine perchlorate 12.0 grams (1 mol.) of 2-ethylmercaptolepidine ethoethylsulfate, 16.6 grams (1 mol.) of 2-18- acetanilidovinylbenzothiazole ethiodide, 8.2 grams (2 moles. +10% excess) oi. triethylamine and '75 cc. of ethyl alcohol were mixed and refluxed 20 minutes and the dye precipitated with an excess of aqueous potassium perchlorate. After chilling the reaction mixture, the dye was filtered off, washed with cold ethyl alcohol, hot water, acetone and crystallized twice from methyl alcohol; (400 cc./gram). The minute bronze crystals melted at 251-253 C. dec.

Ema'mple 12.1-eth' Z-4-(3-ethyl-2(3H) -beneoaaeolylidene) propenylthiocarbostyrz'l Example 13.1 ethyl 4 (3 ethyl 2(3H) benzothz'aeolylidene) propenylthiocarbostyril 2.60 grams (1 mol.) of 1-3-diethyl--2'-ethylmercaptothia-4-carbocyanine perchlorate, 0.98

gram (1 mol. +25% excess) of anhydrous sodium sulfide. and 30 cc. of anhydrous ethyl alcohol were refluxed 5 minutes during which time the deep blue color of the reaction mixture was replaced by a reddish coloration. After chilling several hours at 0 C., the green crystals were filtered off, washed With a few cc. of cold ethyl alcohol,

then a large quantity of hot water and cold methyl alcohol. The dye was purified by dissolving in pyridine and precipitating with methyl alcohol. The minute green crystals melted at 243246 C. dec.

The above examples are merely illustrative, and it is to be understood that various modifications can be made in accordance with the general description given above.

What I claim as my invention and desire secured by Letters Patent of the United States is:

1. A cyanine dye selected from those represented by the following general formula:

wherein R and R1 each represents an alkyl group containing from 1 to 4 carbon atoms, d and n each represents a positive integer of from 1 to 2, Q represents a member selected from the group consisting of a nitrogen atom and a -CI-I=group, X represents an acid radical, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of those of the thiazole series, those of the benzothiazole series, those of the naphthothiazole series, those of the thianaphtheno-7',6,4,5-thiazole series, those of the oxazole series, those of the benzoxazole series, those of the naphthoxazole series, those of the selenazole series, those of the benzoselenazole series, those of the naphthoselenazole series, those of the thiazoline series, those of the 2-quino1ine series, those of the l-quinoline series, those of the l-isoquinoline series, those of the 3-isoquinoline series, those of the 3,3-dialkyl- ,indolenine series, and those of the pyridine series.

2. A cyanine dye selected from those represented by the following general formula:

wherein R and R1 each represents an alkyl group containing from 1 to 4 carbon atoms, at and n each represents a positive integer of from 1 to 2, X represents an acid radical, and Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in the heterocyclic ring.

3. The cyanine dye having the following formula:

( zHa 4. The cyanine dye having the following formula:

7. The cyanine dye having the following formula':

8. A process for preparing cyanine dyes comprising condensing together a compound selected from those represented by the following general formula:

wherein. R represents an alkyl group containing from 1 to 4 carbon atoms, Q represents a member selected from the group consisting of a nitrogen atom and a CI-I=group, and X represents an acid radical, and a compound selected from those represented by the following two general formulas:

and

wherein R1 represents an alkyl group containing from 1 to 4 carbon atoms, R2 represents a member selected from the group consisting of an alkyl group containing from 1 to 2 carbon atoms, a

phenyl group, and a tolyl group, R3 represents an acyl group of a carboxylic acid, R4 represents a mononuclear aromatic group, n represents a positive integer of from 1 to 2, X1 represents an acid radical, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus seiected from the group consisting of those of the thiazole series, those of the benzothiazole series, those of the naphthothiazole series, those of the oxazole series, those of benzoxazole series, those of the naphthoxazole series, those of the selenazole series, those of the benzoselenazole series,

those of the naphthoselenazole series, those of the thiazoline series, those of the thianaphthenoseries, those of the e-quinoline series, those of the l-isoquinoline series, those of the 3-isoquinoiine series, those of the 3,3-dia1ky1indo1enine series, and those of the pyridine series.

9. A process according to claim 8 wherein the condensation is carried out in the presence of a basic condensing agent.

10. A process according to claim 9 wherein the basic condensing agent is triethylamine.

References Cited in the file of this patent UNITED STATES PATENTS Name Date I-Ieimbach June 8, 1948 Number

Claims (1)

1. A CYANINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: