US2677683A - Cyclammonium quaternary salts and dyes produced thereof - Google Patents

Description

Patented May 4, 1954 CYCLAMIWONIUM QUATERNARY SALTS AND DYES PRODUCED THEREOF Paul Daniel Dreyfuss, Van Nuys, and Bela Gaspar, Beverly Hills, Calil-Z; said Dreyfuss assignor to said Gaspar No Drawing. Application May 17, 1949, Serial No. 93,818

3 Claims. 1

This invention relates to cyclammonium quaternary salts, to a process for preparing them, and to dyes made therefrom.

A class of intermediates of great value for the preparation of polymethine dyes consists of the cyclammonium alkyl quaternary salts having the following structure where A stands for a methyl or a substituted methyl group; R stands for an alkyl group; X stands for an anion, and Y stands for a chain of from two to three carbon atoms.

Some of these cyclammonium alkyl quaternary salts are available by condensing the bases with alkyl halides or alkyl toluenesulfonates, RX. The condensation of these bases with the corresponding aryl derivatives, however, is not possible; i. e., the cyclammonium salts of the above indicated structure where R stands for an aryl residue, cannot be obtained by the usual methods.

In the co-pending applications entitled "N- Arylthiazolinium Quaternary Salts and Penthiazolinium Quaternary Salts, filed on an even date herewith, it is disclosed that thiazolinium and penthiazolinium quaternary salts can be obtained by condensing thioamides A--CSNHR with compounds X-Y-X, where A and Y have the above explained meaning, where R stands for an alkyl or an aryl residue and Where X stands for a residue which is able to accept an electron to form an anion, such a a halogen atom or an alkylsulfo or arylsulfo residue. The residue X which functions as an anion in the quaternary salt and as a homeopolar substituent in the starting material from which quaternary salt is obtained, is called anionide substituent in the appended claims.

We have now found a new method for preparing cyclammonium quaternary salts of the above type where It stands for alkyl or aryl. By means of our new method many quaternary salts, heretofore unknown, are made available for the first time.

In accordance with our invention, we prepare the cyclammonium quaternary salts by condensing one mol of a compound RNHY-X with one mol of a compound ACSNB2, where Y, X and A have the explained meaning; where R stands for alkyl or aryl, and where B stands for hydrogen or its equivalents. The condensation is performed preferably in the presence of one mol of an acid, HX, which serves to stabilize the compound RNH-YX which otherwise tends to condense with itself, and to bind the base NHBz liberated in the condensation. The condensation follows the following scheme:

Most of these condensations are exothermic, starting at temperatures below 200 and giving excellent yields. The starting materials are easily available; the condensations are easily performed; the reaction is highly versatile, rendering accessible substituted thiazolinium and penthiazolinium salts which cannot be obtained by any other method. These features make our invention a valuable instrument in obtaining cyclammonium quaternary salts and dyes derived thereof.

The formation of a cyclammonium R. quaternary salt from the components R-NH-YX and ACS-NB2 is unexpected. Gabriel and coworkers [Berichte 27, 3519 (189a); ibid. 29, 2610 (1896) prepared bases from NH2YX and A-CSNI-I2. It seemed probable that the ammonia liberated in Gabriels reaction was furnished from the component 3 NI-I2YX while the thiazoline nitrogen was furnished from the thioamide. This mechanism seemed probable particularly in view of Todd et a1. [Berichte 69, 217 (1936)] who found that from thioamides, A-CSNHB, cyclammonium B quaternary salts can be obtained.

According to our invention, however, the residue B in the thioamide influences the ease but not the course of the reaction, 1. e. the same cyclammonium R quaternary salt is obtained whether thioacetyl amide, methylamide, xylidide, bromanilide or naphthalide are condensed with compounds Pr--NH-Y-X.

Suitable compounds A--CSNB2 in the synthesis according to this invention are e. g. the following:

Thioacetamide Thioacetanilide Thiopropionamide Thiobutyramide ,c-Methoxy thiopropionamide a-Phenyl thioacetamide u-Methoxy thioacetamide a-Phenoxythioacetamide s-Ethylthioglycolic acid thioamide Other thioamides such as thioformamide, thiobenzamide or thioterephthalamide (which can be reacted with compounds RNHY--X in proportions 1:1 or 1:2) are equally suitable in the preparation of cyclammonium R quaternary salts.

The compounds RNHY-X used in our invention are preferably obtained from the corresponding alcohols R--NHY-OH and isolated as salts RNH-YX, HX, e. g., the alcohols can be converted into the bromo compounds, according to the method described by Pearlman, Journal of the American Chemical Society, vol. '70, page 871 (1948), or into the sulfuric acid esters such as described by Emde, Helvetica Chimica Acta, vol. 12, page 402 (1929). Other methods of conversion of alcoholic groups (OH) into anionide groups (X) are well known in the art.

Typical of suitable compounds RNH--YOH are:

c-Methylaminoethanol B-Isoamylaminoethanol -A11ylaminoethanol c-Cyclohexylaminoethanol B-Anilinoethanol p-p-Toluidinoethanol B-o-Chloranilinoethanol B-p-Ethoxyanilinoethanol p- 1 -naphthylamino) ethanol 5- (Z-naphthylamino) ethanol 2- s-hydroxyethylamino diphenylene oxide fl-n-Propylamino-n-propanol ,c-Anilino-n-butanol fl-Ethylamino-isopropylalcohol (fl-Hydroxy-v-phenoxypropyl) -aniline Ephedrine Conhydrine Pseudoconhydrine 2-methylaminocyclohexanol 3 -methylaminoborneol 1,2,3A-tetrahydro-3-hydroxybenzo [h] quinoline 1,2,3,4 -tetrahydro-2-hydroxy-benzo [f quinoline N,N'-di- (B-hydroxyethyl) -p-p-henylenediamine a-Phenyl-p-anilinoethanol a,fl-Diphenyl-c-p-chloroanilinoethanol Methyl-a-pyrrolidylcarbinol v-Ethylaminopropanol -Cyclohexylaminopropanol 4 -Anilinopropanol 'y-o-chloranilinopropanol v-p-Ethoxyanilino-n-butano1 (1-naphthylamino) propanol v-Methylamino-n-butanol 4-hydroxypiperidine 2- (fl-hydroxyethyl) piperidine (2-hydroxy-hexahydrobenzyl) aniline Nortropine In addition to the compounds RNHY-X which are obtained from the alcohols of the foregoing list, there are a few which are obtained from other starting materials; such compounds are, e. g.: 'y-chloro- 3-hydroxypropylaniline, and o-(methylamino) benzylbromide.

By combination of thioamide RFCs-N132 with compounds RNH-YX a most diversified roup of cyclammonium R quaternary salts is available. The carbon chain, represented by Y, is in most cases saturated. Of particular interest are thes compounds in which said carbon chain Y is substituted. The substituent are primarily hydroxyl groups, aliphatic or aromatic groups, but other substituents such as nitrile, sulfone, sulfonamide groups which do not interfere with the cyclammonium salt formation are within the scope of the present invention. Member of the chain Y can furthermore be part of rings. For example, by melting thioacetamide with 4-iodopiperidine hydroiodide, a compound is obtained 1which is believed to have the following constitu- 1011 and from N-methylhexahydro-o-chloroaniline another typ of dicyclic compound is obtained, i. e., a hexahydrobenzthiazolium quaternary salt. The following examples will serve to illustrate further the manner of obtaining cyclammonium quaternary salts and of preparing dyes thereof.

EXAMPLE 1 2-methyZ-3-ethyl thiazolinium perchlorate FormulaI w XHO/ s J I Hi /CCH| N/ Y/ z Twenty-three grams of B-bromo-diethylamine hydrobromide and 7.5 grams of thioacetamide were mixed and heated in a boiling Waterbath for 20 minutes. The mass melted but thickened again after a short time. The mass was dissolved in 30 ml. of water, and a solution of 20 gr. of sodium perchlorate in 20 m1. of water was added. The quaternary thiazolinium perchlorate separated in crystalline form. It was filtered and washed with isopropylalcohol. By recrystallization from isopropylalcohol the perchlorate was obtained as colorless crystals, melting at -81 C. The yield was 17.2 grams (75% of theory).

EXAMPLE 2 Z-methyZ-S-ethyl thiazolinium iodide (Formula I: W:- XzH; Y:C H Zzl) Twenty-three grams of B-bromodlethylamine hydrobromide and 7.5 grams of thioacetamide were melted as in the foregoing example. The mass was slurried in isopropylalcohol and filtered. The residue was ammonium bromide. The filtrate was warmed, a warm solution of 15 grams of sodium iodide in isopropylalcohol was added, and the precipitated sodium bromide was filtered off. The filtrate (200 ml.) was cooled whereby the quaternary iodide crystallized. The raw iodide was highly hygroscopic. It was suspended in boiling acetone to which methanol was added dropwise until the crystals dissolved completely. The pure iodide crystallized by cooling. It was identical in every respect with the salt prepared according to Brooker, Journal of American Chemical Society, vol. 58, page 664 (1936).

EXAMPLE 3 2-methyl-3-phenylthiazolinium iodide (Formula: W: XzH; Y:C H Z:I)

Twenty-eight grams of N-[i-bromoethylaniline hydrobromide, 7.5 grams of thioacetamide and 30 ml. of chlorobenzene were stirred and heated in an oil bath for one hour, starting at 95 C. and raising the temperature up to 110 C. While heated, the mass first dissolved and shortly afterwards solidified again. After cooling, the mass was filtered, washed with 40 ml. of commercial ether and digested in 100 ml. of boiling isopropylalcohol. Without separating the solid ammonium bromide, 15 grams of sodium iodide were added, the mixture of ammonium and sodium bromides were removed by filtration through a heated Biichner filter, and the residue was extracted with 50 ml. of hot isopropylalcohol. The combined filtrates were cooled whereby the quaternary iodid crystallized. The crystals were filtered oiT, and the filtrate served for a further extraction of the above inorganic residue whereby a second crop of quaternary iodide was obtained. The iodide, recrystallized from isopropylalcohol, formed colorless crystals melting at 181-l82 C. The yield was 25.7 grams (84% of theory).

If smaller batches than that above are run, the mixture of the components may be melted without a solvent. However, if the temperature is not carefully watched, the reaction gets out of control and the raw product then will contain appreciable amounts of a yellow dye, decreasing the yield. The reaction is much smoother in the presence of a solvent such as chlorobenzene. reaction was successfully run in isopropanol, and even in water and in diluted aqueous hydrochloric acid the quaternary salt formed, but the yield was considerably smaller.

If the thioacetamide is replaced with an equiva lent amount of thioacetanilide, the same quaternary salt and, as byproduct, aniline hydrobromide is formed. However, if thioacetanilide is melted with bromoethylamine hydrobromide, no quaternary salt forms; only aniline hydrobromide and 2-methylthiazoline can be isolated from the re action mixture.

If thioacetamide is melted with free bromoethylaniline, ammonia gas escapes, and a residue is obtained which consists partly of diphenyl- The '6 piperazine and partly of quaternary salt from which the iodide, melting at 181-182 C. can be obtained in only inferior yield.

EXAMPLE 4 2-methyl-3-phenylthiazolinium bromide (Formula I: W:;X:H; Y:CGH5;Z:B1\)

An intimate mixture of 28 grams of N-B- bromoethylaniline hydrobromide and 7.5 grams of thioacetamide was heated to C. When the reaction started to become violent it was moderated by cooling, and after the reaction subsided, the mass was heated to 100 C. for one hour. The mass was extracted with isopropanol, and from the extract the quaternary bromide crystallized. It was recrystallized from isopropyl alcohol, forming colorless crystals, melting at 204 C.

EXAMPLE 5 2-methyl-3-phenylthiazolinium perchlorate (Formula I: W: ;X:H; Y:C0H5;Z:C1O4) The melted mass, obtained as in the foregoing example, was dissolved in water and precipitated with sodium perchlorate. The product, recrystallized from ethanol, formed colorless crystals, melting at C.

EXAMPLE 6 2-meth,yl3-phcnylpenthiazolinium perchlorate (Formula I: W:Cl-l X:H; Y:CGH5 Z: C10,)

Fifteen grams of N-y-bromopropylaniline hydrobromide and 3.8 grams of thioacetamide were melted for 15 minutes in a boiling water bath. The mass was dissolved in water and precipitated with sodium perchlorate. 8.0 grams of pure perchlorate, melting at 129 C. were obtained.

-Hydroxypropylaniline, serving as starting material for the bromopropylaniline of this example, could be obtained in good yield by heating trimethylene chlorohydrin with a 100% excess of aniline in water in the presence of traces of potassium iodide.

EXAMPLE '7 By condensing N-vbromopropyl-ethylamine hydrobromide with thioacetamide and proceeding as in Example 3, a penthiazolinium iodide (Formula I: W=CH2; X=H; Y=C2H5; Z=I) was isolated which was identical with the Z-methyldihydro-1:3-thiazine ethiodide, described by Hamer and Rathbone, Journal of the Chemical Society, 1943, page 247.

The melting points of other quaternary salts, prepared by the same method, are reported in the following table:

[Formula I: Z:ClO

The a-phenyLfi-(cyclohexylamino) ethanol, M. P. 89 C., obtained from cyclohexylamine and phenylethylene oxide, easily decomposes if boiled with aqueous hydro bromic acid. However, it can be converted into N-(B- promo-B-phenylethyl) cyclohexylamine hydrobromide, serving as starting material in the preparation of quaternary salt #3, by heating with aqueous hydrobromic acid (48%) for only 15 minutes at waterbath temperature.

EXAMPLE 8 3,3'-diphenylpenthiazolino carbocyam'ne perchlorate Formula II w w X-HC/ s s \CHX Hi C-(OH=CH)..CH=C on,

N N I Y z Y Two and nine-tenths (2.9) grams of 2-methyl- S-phenylpenthiazolinium perchlorate and 2.2 grams of ethyl orthoformate in 10 ml. of anhydrous pyridine were refluxed for one hour. The dye was precipitated with ether and recrystallized from methanol. It was a brown powder which, after previous shrinkage, melted at about 210 C. The methanol solution of the dye had an absorption maximum at about 483 mu while the absorption maximum of a pyridine solution was at about 4.90 mu. The sensitivity range of a silver chlorobromide emulsion containing 20 mg. of the dye per liter emulsion extended to about 540 mu with a maximum at about 510 mu.

EXAMPLE 9 Other symmetrical carbocyanine dyes are I listed in the following table:

infra-red range, are prepared from 2 mols of quaternary salt and 1 mol of glutacondialdehyde in cold pyridine with triethylamine. The absorption maxima of some of these dyes are reported in the following table:

Unsymmetrical carbccyanines derived from the quaternary salts of this invention are represented by the dye I C211 I C 5H5 which forms reddish brown crystals melting at 268 C. The methylalcoholic solution absorbs with a maximum at about 541 mu. A silverbromide emulsion is sensitized in the long-wave green range of the spectrum.

These unsymmetrical carbocyanines can be obtained e. g., by condensing the quaternary salts of this invention with equimolecular proportions of other quaternary salts in the presence of ortho esters or acid anhydrides. They can be obtained furthermore by condensing 2-methy1 quaternary salts with 2-arylamino vinyl quaternary salts. A method for obtaining meso methyl substituted unsymmetrical cyanine dyes consists e. g., in condensing the quaternary salts of our invention, or derivatives thereof, with reactive compounds such as methylene bases, in suitable solvents whereby Formula II: n=l Absgiiggtlon ma um Appearance M. P. of methanol W X Y Z solution, mu

H CzHr- I Brown crystals with 255 455 metallic luster. H OtH5 I Brown crystals with 253 465 bronze luster. 0015- cyclohexy1-.. 0104 Orange needles Hi l-166. 458 GH-- H 02H5- I Red crystals 243 465 CH; C@H5- 0104 Brown p0wder Decomp... 470

All of these dyes sensitize chlorobromide emulsions with maxima in the range between 475 and 500 mu, the penthiazolino carbccyanines (W=CH2) imparting a sensitizing maximum at a longer wave length than the thiazolino carbocyanines (W=-), and the N-aryl carbccyanines 5 (Y=aryl) at a longer wave length than the N-alkyl carbocyanines (Y=alkyl).

EXAMPLE l0 0 If 2 mol equivalents of quaternary salt and 1 7 mol equivalent of propenedianilide are condensed in pyridine with trimethylamine, dicarbocyanine dyes form which are strong red sensitizers. The analogous triearbocyanines which sensitize in the part of the cyclammonium derivatives decompose furnishing the acid derivatives necessary for the formation of the polymethine chain. For example, the dithio acid which is obtained from 2-methyl-3-phenylthiazolinium iodide, carbon disulfide and triethylamine in methanol and which melts, depending on the rate of heating, between and C. is a suitable starting material for meso mercapto dyes (upon addition of alkyl halides) and for meso methyl dyes. Said dithio acid, if refluxed with methylbenzthiazole ethiodide in ethanol for thirty minutes, is converted into the carbocyanine of the above formula.

Analogous dyes are obtained by heating 2- methyl 3 phenylthiazolinium iodide with lacetylmethyl-Z-ethylbenzoselenazoline in propionic anhydride, by condensing S-B-naphthylthiazoline-2-methine-w-aldehyde with l-ethyl- Z-methyl-3-phenylbenzimidazolium ethyl sulfate or by condensing the 2-(2-acetanilidovinyl)- 3-phenylpenthiazolinium perchlorate, disclosed below, with methylbenzoxazolium ethyl iodide.

The quaternary salts of our invention, which have attached in the 2-position a sidechain -CH2-R where R. stands for hydrogen or its equivalents, can be condensed with diary]- formamidines to give ,8-arylaminovinyl derivatives thereof. They can also be condensed with diarylformamidines in the presence of acid anhydrides such as acetic anhydride, propionic anhydride and butyric anhydride to give ,S-acyb arylarninovinyl derivatives thereof. These B- acylarylarninovinyl cyclammonium quaternary salts can be obtained as well by first fusing the Z-methyl-cyclammonium quaternary salts with a diarylformamidine, followed by acylation with an acid anhydride.

EXAMPLE 12 Z-(Z-anilino vinyl) -3-phenylpenthiazolinium perchlorate Formula III (V CHB-CO which can be obtained e. g., by acetylation of the foregoing compound with acetic anhydride, forms colorless needles, melting at 182183 C.

EXAMPLE 13 In a similar manner other p-arylaminovinyl quaternary salts and their acyl derivatives can be prepared. Some of these are shown in the following table:

[Formula III: Y=GuHr; W=.]

M. P. V X Z Appearance degrees H H I Yellow needles 214-215 CH3OO- H I Nearly colorless crys- 188-190 a s. H CH; 0104 Yellow crystals 184 H H C Orange needles 191-192 1 One preparation of 2-anilidovinyl-3-phenylthiazolinium perchlorate yielded light yellow prisms (from ethanol), melting at 172- 173 C. The melt, scratched with the higher melting modification (of previous preparations, solidified againand melted then at 19l-192 These p-arylaminovinyl quaternary salts and their acyl derivatives can be converted into merocyanines by condensation with heterocyclic compounds where D stands for oxygen or sulfur and where U stands for the non-metallic atoms necessary to complete a heterocyclic nucleus, or with other compounds having a reactive methylene group. The condensations are effected in the presence of an acid-binding agent, such as pyridine, trialkylamine, piperidine, dimethylaniline, etc. The acylarylaminovinylcyclammonium salts, such as 2-w-propionanilidovinyl-B-phenylpenthiazolinium perchlorate, condense with particular ease, and the condensation therefore can be carried out even at room temperature. The arylaminovinylcyclammonium salts, such as 2-w-anilidovinyl-3- phenylpenthiazolinium perchlorate, however, are best condensed with the heterocyclic compounds at elevated temperature. The following example will serve to illustrate further the manner of obtaining such merocyanine dyes.

EXAMPLE 14 3-n-hewyZ-5- (3-phenyZ-2 (3) thiazolinylidene) ethylz'dene] rhodanine Formula IV Two and two-tenths (2.2) grams of N-n-hexylrhodanine (0.01 mol) and 4.2 grams of 2-(2-anilidovinyl)-3-phenylthiazolinium iodide (0.01 mol) were refluxed in 10 ml. of ethylalcohol with 1.4 ml. of triethylamine for two hours. By cooling, the dye crystallized; it was recrystallized from methanol and formed orange-red needles, melting at 87-88 C. Yield 3.8 grams. The solution of the dye in methanol had an absorption maximum at about 488 mu.

The dye sensitized a photographic silver bromide emulsion to about 590 mu with maximum sensitivity at about 545 mu. It is preferably used in a concentration of from about 5 to about 50 mg. per liter emulsion.

The N-n-hexylrhodanine, used in the preparation of this dye, was prepared from n-hexylamine, carbon disulfide and chloracetic acid in the usual manner, and was a viscous oil, boiling at C./2 mm.

EXAMPLE 15 Other merocyanines, most of them obtained from anilidovinyl cyclammonium salts, are reported in the following table:

' ponents.

substituted dyes (7 to 9) are at a little longer TABLE OF MEROOYANINES Formula IV Absorpt, Inax$um T W x Y Appearance M. P ,;,f at Q A=1n acetone 1 1 N-phenylrhodan- H CH3 0 H; Orange crystals (from 229 11:485.

ideue. acetone). 2 N-ethylrhodanyl- H CH3 1x01130 11; Fire-red crystals (irom 157-168 A2485.

idene. acetone and methano 3 l N-phenylrhodan- H OH H 0 H; Orange crystals (from 11:405.

ylidene. acetone). 4 1 N-ethylrhodanyl- H CH II 0411 Fire-red crystals (from 153-155" A2492.

idene. acetone and methan 5 1 Phenylmethylpy- H CH H C H Yellow needles (from 177 A: 420.

razolonylidene. methanol). 6 2 N-n-hexylrl1odan- H II 05115 Metallic soft blue crys- 90-145", depend- M2610.

ylidene. tals (from benzene ing on rate of and ligroine). heating 7 1 do CH H n-C4H Red crystals (from eth- 123-124 Mz488.

ano 8 1 do CH; H 00H}; Redcrystals(frompyrl- 142 Mz488.

dine and methanol). 9 1 do OH3S H 0511 Red crystals (from ace- 132133 A:515.

ne 10. 1 3-n-hcxyl-2-thio-2, H H OaH Yellow crystals (from 82-83 Mz455.

ldoxazolonylmethanol). 1 one. ll 1 3-ethyl'2-thio-2,4 H H C 11 Rust brown crystals 186-187" 1:444.

4-oxazolonyl- (from acetone and idene. methanol) 12 1 N-ethylrhodanyl- H H O5H Orange plates with me- 179 M2485.

idene. italllt): luster (from aceone The merocyanines 1 to 4 and 7 to 12 are strong green sensitizers for silver bromide emulsions and particularly suitable'for colorphotographic emulsions containing tinctorial dyes or dye com- The sensitizing maxima of the meso wavelength than those of analogous dyes having an unsubstituted polymethin chain (1 to 6; 10 to 12) the sensitizing maxima of the penthiazolino dyes (3 to 5) are at a little longer wavelength than those of analogous thiazolino dyes (1, 2, 6

to 12); and the sensitizing maxima of the dyes derived from N-arylcyclammonium salts (1 to 6, 8 to 12) are at a little longer wavelength than those of analogous dyes derived from N-alkylcyclammonium salts (7).

Substitution in the cyclamine residue (#1 and #2 of the foregoing table causes only minor shifts of the sensitizing maximum but influences the afiinity of the dye to silverhalide grains, 1. e.,

it influences the sensitizing intensity and-in color photographic multi-layer materials-the resistance to diffusion into adjacent layers and the resistance to desensitizing effects by tinctorial dyes or dye components.

By lengthening the polymethine chain (6) excellent red sensitizers are obtained. These dyes are prepared, g., by condensing the quaternary salts of this invention with propenedianilide (1:1) and by further condensing the intermediates hereby obtained with heterocyclic compounds such as rhodanine. The sensitizing characteristics are further influenced by the radical (Q) which can be unsubstituted rhodanine, a substituted rhodanine such as N-(fi-hydroxyethyl) rhodanine, N (,8 carboxyethyl) rhodanine, N-(B-sulfoethyl) rhodanine or which can be another heterocyclic compound such as a thiooxazoledione (e. g., 3-methyl-2-thiooxazoledione), thiohydantoin (e. g., 3-ethyl1- phenyl-Z-thiohydantoin), thiobarbituric acid, pyrazolone, thiopyrazolone, thionaphthenone, or which can be an acyclic compound such as malonic nitrile, etc. For example, the N-hexylthiooxazoledione merocyanine (#10 of the foregoing table) sensitizes at a shorter wavelength than does the corresponding N-hexylrhodanine merocyanine of Example 14. It is therefore possible to prepare merocyanines from the quatenary salts of this invention which are blue, green, red or infra-red sensitizers; and by convenient variation of the above mentioned variables, sensitizers can be produced for nearly each wavelength of the spectrum.

The merocyanines of the preceding examples, 14 and 15, can be modified by addition of alkyl halides (RX), and the salts thereby obtained can be condensed with quaternary salts to give valuable trinuclear carbocyanine dyes.

Other dyes, such as styryls, pseudocyanines, isocyanines, hemicyanines, can be obtained from the quaternary salts of our invention by methods well known in the art.

The dyes of this invention may serve for sensitizing photographic silver halide emulsion, e. g., according to the following procedure: A quantity of the dye is dissolved in a suitable solvent, such as an acetone-dioxane mixture or aqueous methanol, and a volume of this solution containing from about 5 to about 100 mg. of dye is slowly added to one liter of gelatino-silver-halide emulsion. If the dye is used in sensitizing a photographic silver bromide emulsion containin a color former or a tinctorial dye, the sensitizing dye may be added to the emulsion before or after the addition of the color former or tinctorial dye, and before, during or after the ripening of the emulsion.

The dyes of our invention can be used in supersensitizing mixtures of dyes. They can be used furthermore as antihalation, filter and desensitizing dyes.

The quaternary salts of our invention, serving as intermediates for photographic dyes, may be used in other fields as well; e. g., they are valuable intermediates in the production of N-substituted arninoalkylthiols and compounds obtained therefrom.

Since from the foregoing description of the invention it will be apparent to those skilled in the art that many variations of this invention may be made without departing from the spirit and scop thereof, it is to be understood that we do Number not limit ourselves to the specific examples there- 1,950,876 of except as defined in the appended claims. 2,054,390 We claim: 2,083,804 1. A merocyanine dye represented by the 2,112,162 formula 2,211,408 CH2 2,213,730 2,312,153 E 2,315,498 1 c= 0H--c )"=oc=o 2,322,015 \N/ 2,330,203 1 2,342,546 2,424,484 2,439,210 2,441,558 2,454,629 wherein n is 1, and U represents the non-metallic ,49 72 atoms necessary to complete a heterocyclic nu- 2, cleus selected from the group consisting of rho- 2, danine and pyrazolone nuclei. 2 2. A merocyanine dye as defined in claim 1 3 wherein n is 1 and U represents the non-metallic 2,552,252

atoms necessary to complete a rhodanine nucleus.

3. A merocyanine dye as defined in claim 1 wherein n is 1 and U represents the non-metallic atoms necessary to complete a pyrazolone nucleus.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,942,854 Brooker Jan. 9, 1934 14 Name Date Brooker Mar. 13, 1934 Rust et al Sept. 15, 1936 Zeh June 15, 1937 Kendall Mar. 22, 1938 Dieterle et al Aug. 13, 1940 Beilenson Sept. 3, 1940 Dieterle Feb. 23, 1943 Brooker Apr. 6, 1943 Hamer June 15, 1943 Brooker Sept. 28, 1943 Kendall Feb. 22, 1944 Middleton et al July 22, 1947 Heimbach Apr. 6, 1948 Brooker May 18, 1948 Brooker Nov. 23, 1948 Anish Dec. 6, 1949 Brooker Jan. 10, 1950 Jennen Jan. 24, 1950 Brooker Oct. 24, 1950 Jennen Mar. 6, 1951 Brooker May 8, 1951 OTHER REFERENCES Chemical Abstracts, vol. 19, p. 530 (abstract of Proc. Roy. Soc., London, 1924, 96B, 317-333).

Chemical Abstracts, vol. 16, p. 3101 (abstract of Brit. Med. Journal, 1922, I, 514-515).

Claims (1)

1. A MEROCYANINE DYE REPRESENTED BY THE FORMULA WHEREIN N IS 1, AND U REPRESENTS THE NON-METALLIC ATOMS NECESSARY TTO COMPLETE A HETEROCYCLIC NUCLEUS SELECTED FROM THE GROUP CONSISTING OF RHODANINE AND PYRAZOLONE NUCLEI.