US3152896A

US3152896A - Magenta-forming couplers

Info

Publication number: US3152896A
Application number: US259392A
Authority: US
Inventors: Robert J Tuite
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1963-02-18
Filing date: 1963-02-18
Publication date: 1964-10-13
Anticipated expiration: 1981-10-13
Also published as: GB1059146A; MY6700160A; BE643777A; NL6401438A; CH429444A; DE1176478B; DK113756B; SE333500B; ES296535A1

Description

United States Patent 3,152,396 MAGENTA-FORMHQG CGUPLERS Robert J. Tuite, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Feb. 18, 1963, Ser. No. 259,? Claims. (Cl. 96-22) This invention is related to color photography and more particularlyto novel 1-aryl-3-anilino-5-pyrazolone magenta-forming couplers and their use in color photography.

The formation of colored photographic images by couplingthe development product, that is, oxidized primary aromatic amino developing agents with color forming or coupling compounds is well known. In these processes the subtractive process of color formation is ordinarily used in which phenolic or naphtholic couplers are used to produce the cyan dye, S-pyrazolone couplers are used to make the magenta dye, and compounds having an active methylene group separating two carbonyl groups are used to form the yellow dye.

Diffusible couplers are used in alkaline developer solutions containing the primary aromatic amino color developing agent to color develop color photographic elements that do not contain the color forming couplers. During color development, the coupler and developing agent as well as other materials in the color developer solution diffuse into the color photographic element being developed with the imagewise formation of oxidized color developer and the subsequent coupling to produce a nondiffusing dye image in the element.

Desirable couplers for color photography must have good coupling activity, and produce dye images in the color developed photographic elements that have the needed spectral absorption characteristics, and dye images that have good stability to prolonged exposure to light. In addition to this, it is important that the coupler and its reaction products not produce yellow stain in the' highlight or D min. areas of the developed photographic elements.

Some of the magenta-forming couplers now in use have good activity and produce dyes with good absorption characteristics but do not produce dyes with the desired light stability. Furthermore, these couplers tend to produce undesirable yellow stain in the D min. areas of the developed elements. Many of the prior art S-anilino-S-pyrazolone magenta-forming couplers are un acceptable because of low coupling activity and undesirable spectral absorption characteristics of the dyes produced from them.

It is, therefore, an object of my invention to provide a new class of 1-aryl-3-anilino-5-pyrazolone couplers which have the desired coupling activity, which do not produce the yellow stains in the D min. areas of developed elements that are produced by prior art l-aryl-3-anilino- S-pyrazolone couplers and which produce magenta dyes having improved light stability and good spectral absorption characteristics.

Another object of my invention is to provide, for use in color photography, valuable magenta-image-forming developer solutions containing my 1-aryl-3-aniliano-5- pyrazolone couplers, said solutions producing unexpectedly low yellow stain in the D min. areas of color photographic elements processed through them.

Another object is to provide valuable magenta-image forming developer solutions which produce magenta dye images having unexpectedly good stability to prolonged exposure to light.

Another object is to provide a color process that uses my valuable l-aryl-3-anilino-5-pyrazolone couplers in a magenta-image-forming developer solution.

Still other objects will become evident from the following specification and claims.

These and other objects are accomplished by the use of my valuable class of l-aryl-3-anilino-5-pyrazolone couplers. My couplers exhibit good coupling activity in magenta-forming developer solutions during color development reactions and produce in the color element being developed, magenta images having desirable sensitometric characteristics, i.e., good D min., D max. and contrast. The use of my couplers in magenta-forming developer solutions results in a substantial reduction in the yellow stain in the D min. areas of color photographic elements developed with them. This valuable improvement shown by my couplers over certain l-aryl-3-anilino-5-pyrazolone outside my invention is unexpected. Furthermore, the dyes formed from my couplers have good spectral absorptions characteristics and are unexpectedly stable upon prolonged exposure to light.

The 1-aryl-3-anilino-5-pyrazolone couplers of my invention are represented advantageously by the following formula:

wherein I represents a group selected from the class consisting of the chlorine atom, the nitro group and the cyano group; W represents a group selected from the class consisting of the hydrogen atom, and the chlorine atom; X represents a group selected from the class consisting of the hydrogen atom, the cyano group and the nitro group; Y represents a group selected from the class consisting of the hydrogen atom, the chlorine atom, the cyano group and the methylsultonyl group; Z represents a group selected from the class consisting of the hydrogen atom, and the cyano group, such that at least one of the groups, W, X, Y and Z represents a group other than the hydrogen atom.

My 1-aryl-3-anilino-5-pyrazolones are used advantageously in aqueous alkaline color developer solutions containing primary aromatic amino developing agents to produce the magenta dye image in the image exposed multicolor photographic element during color development.

In a process well known in the art for the color development of an image exposed multilayer, multicolor photographic element comprising a support having coated thereon a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a bluesensitive silver halide emulsion layer, said process comprising the steps of:

(1) Developing a silver halide negative image in each of said silver halide emulsion layers,

(2) Washing in water,

(3) Selectively re-exposing the unexposed and undeveloped silver halide in the said red-sensitive layer,

(4) Cyan color developing the said re-exposed undeveloped silver halide in said red-sensitive layer with an aqueous alkaline developer solution containing a diffusible cyan-forming coupler and a primary aromatic amino color developing agent,

(5) Washing in water,

(6) Selectively re-exposing the unexposed and undeveloped silver halide in the said blue-sensitive layer,

(7) Yellow color developing said re-exposed and undeveloped silver halide in said blue-sensitive. layer with an aqueous alkaline developer solution containing a s,152,sss

difiusible yellow-forming coupler and a primary aromatic amino color developing agent, (3) Washing in water,

(9) Fogging the unexposed and undeveloped silver halide in the green-sensitive emulsion layer,

(10) Magenta color developing said fogged silver halide in the green-sensitive layer with an aqueous alkaline magenta developer solution containing a diffusible magenta-forming coupler and a primary aromatic amino color developing agent,

(11) Washing in water,

(12) Bleaching to convert said silver image to silver halide,

(13) Fixing to remove silver halide,

(14) Washing and drying,

the improvement according to my invention comprises the use in said magenta developer solution of one of my laryl-3anilino-S-pyrazolone couplers as the magenta image-forming coupler.

The couplers of my invention are prepared advantageously by a general synthesis for making 1-aryl-3- anilino-S-pyrazolone couplers. In this synthesis an aryl hydrazine is. mixed and heated with a methyl ,G-methyh mercapto-fi-aryliminopropionate. This reaction is believed to occur according to the following equations:

1) NAr AINHNH; CHgS-C CHzC 011 NHAr ArNHN=O CHQSH CHZCO2CH3 (11) NHAr heat ArNHN=O or NaOCH CHgCHzCHa I (I) OHgiJ-OH N==CNHAr ArN\ CHsOH wherein Ar and Ar are aromatic groups substituted or not. This reaction can be stopped at the formation of the amide hydrazone, the product of Equation 1, but in most instances it is preferable to proceed to the final cyclized l-ary1-3anilino-S-pyrazolone by further heating. When Ar is a 2,6-disubstituted phenyl group, it is usually better to isolate the amide hydrazone, and cyclize in a separate step with sodium methylate. The methyl ,B-methylmercapto 8-aryliminopropionates used in this synthesis are prepared by a series of reactions in which ethyl acetoacetate is treated with an alkali metal methylate, such as sodium methylate in a solvent, such as methyl alcohol, and the resulting sodio acetoacetic ester formed is then treated with an aryl isothiocyanate in methyl alcohol while heating.

The reaction is used to advantage with any isothiocyanate which is not attacked irreversibly by the sodio acetoacetic ester at another substituent. The isothiocyanates used can be prepared by any of several methods, the most commonly used methods for making aryl isothiocyanates being the method described by Dyson, Organic Synthesis, coll. vol. 1, p. 165, and the method described by Dains, Brewster and Olander, Organic Synthesis, coll. vol. 1, p. 447.

Any arylhydrazine can be used to advantage. If the hydrazine molecule contains a free sulfo or carboxy group, the method is modified to include a mole of a tertiary amine, such as, pyridine or triethylamine, to keep the hydrazine in solution in the refluxing methyl alcohol. Several arylhydrazines are commercially available, either placement with hydrazine.

This synthesis is used to advantage for the preparation of a wide variety of l-aryl-3anilino-S-pyrazolone couplers, including for example, the ditiusible couplers with or without solubilizing groups, ballasted or nondiifusible couplers with or without solubilizing groups, colored couplers (i.e., couplers that are colored), etc.

In addition to introducing solubilizing groups by direct synthesis of a carboxy', sulfo, carbalkoxy, or halosulfonyl coupler followed by a hydrolysis (if necessary) sulfo groups can be introduced by sulfonation of the 5-pyrazolone after its synthesis by my new method. A sulfo group is introduced into the anilino ring under mild conditions, and a sulfo group is introduced into the l-phenyl ring at about to C.

Ballast groups can be introduced by use of ballasted arylhydrazines or aryl thiocyanates, or by any of several methods which have been described previously.

Included among the 1-aryl-3anilino-S-pyrazolones of my invention are the following illustrative examples. (1) 1 (2,4,6 trichlorophenyl) 3 (4 methylsulfonylanilino) 5 pyrazolone These and other 1-aryl-3-anilino5-pyrazolone couplers of the invention are used to advantage in color developing solutions to develop magenta images in light-sensitive elements (which do not contain the color-forming coupler) used for color photography. Any of the well known primary aromatic amino color-forming silver halide developing agents, such as, the phenylenediamines, e.g., N,N-diethyl-p-phenylenediamine hydrochloride, N-methyl-p-phenylenediamine hydrochloride, N,N-di nethyl-pphenylenediamine hydrochloride, 2-amino-5-N,N-diethylaminotoluene hydrochloride, Z -amino-S-(N ethyI-N-Iauryl)t0luene. N ethyl [3 methanesulfonamidoethyl 3- methyl-4-aminoalinine sulfate, N-ethyl-fl-methanesulfonamidoethyl 4 aminoaniline, 4 N ethyl N ,8 hydroxyethylaminoaniline, etc., the p-aminophenols, and their substitution products when the amino group is unsubstituted may be used in the alkaline developer solution with my couplers. Various other materials may be included in the developer solutions depending upon the particular requirements, for example, an alkali metal sulfite, carbonate, bisulfite, bromide, iodide, etc.

The following examples will illustrate the use of typical couplers of my invention and show their unexpected properties.

' EXAMPLE 1 A multilayer, multicolor photographic material comprising a support coated in succession with a red-sensitive cyan-forming silver halide emulsion layer, a greensensitive magenta-forming silver halide emulsion layer,

5. a yellow filter layer, and a blue-sensitive yellow-forming silver halide emulsion layer was exposed to a step wedge in a sensitometer. Pieces of this element were processed as follows: l-minute treatment in a conventional alkali metal bisulfite-formalin prehardener, washing, 2 /2-minute development in a conventional p-methylaminophenol sulfate-hydroquinone black-and-white developer, washing, fogging the unexposed and undeveloped silver halide, 7-minute treatment in magenta color developer solutions, Washing, bleaching, fixing and Washing. The magenta color developer solutions used had the composition:

Magenta Color Developer Sodium hexametaphosphate g 1.0 Sodium sulfite g 5.0 ,4-amido-N-ethyl-N-(B-methanesulfonamidoethyl)-m-toluidine' sesquisulfate monohydrate g 40.0 Trisodium phosphate 40.0 Potassium bromide Sodium sulfate Potassium iodide C-itrizinic acid communique Sodium thiocyanate 1.0 Coupler mole .006 Carbowax 4000 g 1.0 Ethylenediamine sulfate g 3.0

Water to 1.0 liter. pH adjusted to 10.8.

Bleach Formula Sodium hexametaphosphateg' Sodium bromide g 1.0 Sodium sulfate g Potassium ferricyanide g Water to 1.0 liter.

Fixing Bath G. Sodium hexametaphosphate 10.0 Sodium sulfite 10.0 Sodium thiosulfate 320.0 Water to 1.0 liter. pH 7.2;

Separate pieces of the exposed multicolor photographic material were given the described process in which the magenta. color developer container the magenta-forming coupler indicated in the following table. The coupler 1 (2,4,6 triclilorophenyl) 3 (4 nitroanilino) 5- pyrazolone which is outside our invention was used as the control. The processed and dried elements were cornpared for yellow stain by determining the optical density in the D min. areas withlight through a blue filter having a cutoff point at 442 mg. The optical density values of each of the processed strips were determined With light through a green filter. The strips were then exposed to a tungsten are light for 3 days and the density values measured again with light through the green filter. The percent fading of the magenta dye at a density of 1.0 and the yellow stain levels in each strip are tabulated This table shows that the magenta dyes formed from my couplers were all more stable upon prolonged exposure to light than was the control. The yellow stain found in the D min. areas of the processed elements was from 23.5 to 35.3% lower than the stain in the control strip. These improvements are unexpected, especially in the results from coupler 5 which is position isomer of the control coupler (that is, coupler Sis 1-2,4,6-trichlorophenyl)-3-(3- nitroanilino)-5-pyrazolone and the control is l-(2,4,6-trichlorophenyl -3- (4-nitroanilino 5-pyrazolone) The couplers in Example 1 all exhibited good coupling activity, that is they formed go d dye images having desirable sensitometric curves (curve relating developed dye density to log exposure). The coupler 1-(2,4,6-trichlorophenyl)-3-anilino-5-pyrazolone which is outside our invention was used in a magenta developer composition described in Example 1. This solution was used in the process described in Example 1 to process a sample of the image exposed multilayer element. This coupler was found to have such low coupling activity that the magneta dye image formed was unusable, that is the D max. and contrast of the dye image were too low. Similarly, we have found that other 1-aryl-3-anilino-5-pyrazolone couplers outside our invention have such low coupling activities that they cannot be used as desired for developing magenta dye images. 7

My couplers are designed for use in processes in which the coupler is incorporated in the developing solution such as those described in Mannes and Godowsky, US. Patent 2,113,329, issued April 5, 1938, Marines, Godowsky and Wilder, US. Patent 2,252,718, issued August 19, 1941, etc. ,7

Example 2 Multilayer, multicolor photographic elements were exposed as in Example 1 and given the complete reversal process described previously. This process included the steps: treatment in a conventional alkali metal bisulfite formalin prehardener, water washing, development in a conventi nal p-methylaminophenol sulfate hydroquinone black and white developer, Water washing, selective reexposure of the red-sensitive layer with a red light, treatment with an aqueous alkaline cyan developer solution containing a cyan-forming coupler and a primary aromatic amino developing agent, water Washing, selective re-exposure of the blue-sensitive layer, treatment with an aqueous alkaline yellow developer solution containing a yel-. lowforming coupler and a primary aromatic amino developing agent, water washing, fogging the unexposed silver halide in the green-sensitive layer, treatment with an aqueous alkaline magenta developer solution containing a magenta-forming coupler and a primary aromatic amino developing agent, Water washing, bleaching, fixing, water washing and drying. A black and White developer solution, a cyan developer solution, a yellow developer solution and a magenta developer solution such as are described by Mannes et al. in US. 2,252,718 were used. One of the exposed photographic elements was given the complete process using a magenta developer containing the control coupler 1-(2,4,6 trichlorophenyl) 3 (4 nitroanilino)-5-pyrazolone, and a second element received the same process using a magenta developer solution contain ing coupler 5 in place of the control coupler. The processed strips were compared as in Example 1. As in Ex ample 1 the element containing dye from coupler 5 showed lower magenta dye fading upon exposure to light and 29.4% less yellow stain in the D min. area than did the control element. 1

Similarly, it can be shown with the multicolor processing that the other couplers of my invention give the same advantages over the control coupler that they did in Example 1. The advantages shown by my couplers are independent of the cyan and yellow dyes so that any of the available cyan and yellow forming couplers can be used to advantage in my process as long as my magenta developer solution is used.

Coupler 1 was prepared as follows. To a methanolic solution of sodium methoxide prepared from 2.3 g. (0.10

g.-atom) of sodium metal in 150 mlJdry methanol was added 13 g. (0.10 mole) acetoacetic ester. The solution was refluxed for 20 min., cooled slightly, and 19.3 g. (0.10 mole) of 4 -'methylsulfonylphenylisothiocyanate was added. The solution was refluxed for min., cooled to 20 C. and 7 ml. (slight excess) of methyl iodide was added.- The solution was allowed to warm to room temperature during 15 min., then was refluxed 15-60 min. The solution was cooled slightly, 21.1 g. (0.10 mole) of 2,4,6-trichlorophenylhydrazine was added, and the solution was refluxed for 22 hr. The reaction mixture was cooled, the precipitated amide hydrazone was separated by filtration, Washed well with methanol and dried.

- The amide hydrazone (44.8 g., 0.10 mole) was added to a solution of 10.8 g. (0.20 mole) of sodium methoxide in 350 ml. methanol. The mixture was refluxed for about 1 hour (30-45 after solution was obtained), cooled, 350 ml. of water added, and the solution acidified with acetic acid. The precipitate was separated by filtration, washed with water, and dried. After recrystallization from acetonitrile, the coupler 1 had a melting point of 267-269 C.

Coupler 2 was prepared by the method used to make coupler 1, but 16.0 g. (0.10 mole) of 4-cyanophefi'ylisothiocyanate was used in place of 4-methylsulfonylphenylisothiocyanate tomake the amide hydrazone. The amide hydrazone, 40-45% yield, M.P. 206-208 C., was then cyclized to form the coupler which was then recrystallized from acetic acid and dioxane to give a product with a melting point of 299-303 C.

Coupler 3 was prepared by the'method used to make coupler 1 but 16.0 g. (0.10 mole) of 3-cyanophenylisothi- Jocyanate was used in place of 4-methylsulfonylphenylisothiocyanate to make the amide hydrazone. The cyclized coupler after recrystallization from dimethylacetamide and ethanol had a melting point of 290-292 C. (dec.).

Coupler 4 was prepared by the method used to make coupler l but 19.5 g. (0.10 mole) of 2-chloro-5- cyanophenylisothiocyanate was used in place of 4-methylsulfonylphenylisothiocyanate to make the amide hydrazone. The coupler made by cycliz'ation of the amide hydrazone was recrystallized from "acetic acid togive a product with a melting point of 259-262 C. (dec.).

Coupler 5 was prepared by the method used to make coupler 1 but 18.0 g. (0.10 mole) of 3-nitropheny1isothiocyanate was used in the reaction to make the amide hydrazone. The coupler made from the cyclization of the amide hydrazone was recrystallized from methanol to give a product melting at 250251 C.

Coupler 6 was prepared by the method used for coupler 1 but 20.4 g. (0.10 mole) of 2,4-dichlorophenylisothiocyanate was used and the final period of reflux was 72-96 hours. The reaction mixture was then filtered to remove a small amount of by-product (apparently the hydrazide formed by reaction of the uncyclized amide hydrazone and excess hydrazine). The filtrate was then added to a solution of 2 parts of sodium methoxide in methanol, refluxed for 30 min. and an equal volume of water added. The reaction mixture was then extracted with ether to remove some dark tarry material. The aqueous solution was acidified with acetic acid, and the precipitate was separated by filtration, washed well with water, and dried. After three recrystallizations from acetonitrile there was obtained a 24 percent yield of product; M.P. 197-201 C.

Coupler 7 was prepared by the method used for coupler 1 but equivalent amounts of 2,4-dichlorophenylisothiocyanate and 2,6-dichloro-4-nitrophenylhydrazine were used. The cyclized coupler was recrystallized from glacial acetic acid to yield the product; M.P. 229-231 C. (dec.).

Coupler 8 was prepared by the method used for were used. The cy'clized coupler was recrystallized from glacial acetic acid to yield the product; M.P. 258-261" C. (dec.). The arylisothiocyana'tes used were prepared by reaction of, the appropriate amine with thiophosgene in an aqueous suspension. The procedure was adapted for use with high melting amines by using high-speed stirring in a Morton flask, thus eliminating the need for an organic solvent. Consistently higher yields than are reported in the literature were obtained by this revised procedure. Most of these compounds have been described in the literature, for example, 4-methylsulfonylphenylisothiocyanate (L. Doub et al., J.A.C.S., 80, 2205 (1958), 4-cyanophenylisothiocyanate (G. M. Dyson et al., J. Chem. Soc. 1927, 436 2-chloro-5-cyanophenylisothiocyanate (Amine; J. I. Blanksma et al., Rec. Trav. Chim., 66, 365 (1947)), 3-nitrophenylisothiocyanate (G. M. Dyson et al., J. Chem. Soc., 125, 1702 (1924)), and 2,4-dichlorophenylisothiocyanate (G. M. Dyson et al., J. Chem. Soc., 1926, 3041). The 3-cyanophenylisothiocyanate had a melting point of 65.5-69- C.

2,4,6-trichlorophenylhydrazineis available commercially. 2,6 dichl0r0-4-nitrophenylhydrazine is prepared by chlorinating 4-nitroaniline by a conventional reaction then diazotizing the 2,6-diehloro-4-nitroaniline with nitrosyl sulfuric acid at 40 C. and reducing the diazo compound to the corresponding hydrazine compound by treating it with stannou's chloride and hydrochloric acid. 2,6-dichloro 4-cyanophenylhydrazine is prepared by chlorinating 4-cyanoaniline, diazotizing the amine with isoamyl nitrite at 0 C. and then reducing the diazo compound'to the hydrazine derivative as described above.

The 1-aryl-3-anilino-5-pyrazolone couplers of my invention are valuable for use incolor photography. My couplers are distinguished from certain other 1-aryl-3- anilino-5-pyrazolone couplers by having good coupling reactivity. They are distinguished from other 1-aryl-3- anilino-5-pyrazolone couplers by producing up to 35.3% less yellow stain in D. min. areas of photographic elements processed through them. The magnet image dyes formed by my couplers have unexpectedly better light stability than couplers outside the invention.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood-that variations and modifications can vbe'eflected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A difiusible magnets-forming coupler having this formula:

consisting of the hydrogen atom, the cyano group, and

the nitro group; Y represents a group selected from the class consisting of the hydrogen atom, the chlorine atom, the cyano group and the methylsulfonyl group; Z represents a group selected from the class consisting of the hydrogen atom, and the cyano group, such that at least one' of the groups W, X, Y, and Z represents a group other'than the hydrogen atom.

2. The magenta-forming coupler 1,)2,4,6-trichlorophenyl) -3 -(4-cyanoanilino) -5 -pyrazolone.

3. The magenta-forming coupler l-(2,4,6-trichlorophen yl -3 3 -nitroanilino -pyrazol one.

4. The magenta-forming coupler 1-(2,4,6-trichlorophenyl -3 2,4-dichloroanilino -5-pyr azolone.

5. The magenta-forming coupler 1-(2,6-dichloro-4- nitrophenyl -3- 2,4-dichloroanilino -5-pyrazolone.

6. The magenta-forming coupler 1-(2,6-dichloro-4-cyanophenyl)-3-(2,4-dichloroanilino)-5-pyrazolone.

7. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and a magenta-forming coupler having the formula:

wherein J represents a group selected from the class consisting of the chlorine atom, the nitro group, and the cyano group; W represents a group selected from the class consisting of the hydrogen atom, and the chlorine atom; X represents a group selected from the class consisting of the hydrogen atom, the cyano group, and the nitro group; Y represents a group selected from the class consisting of the hydrogen atom, the chlorine atom, the cyano group and the methylsulfonyl group; Z represents a group selected from the class consisting of the hydrogen atom, and the cyano group, such that at least one of the groups W, X, Y, and Z represents a group other than the hydrogen atom.

8. An aqueous alkaline magenta-forming color developer solution of claim 7 in which the primary aromatic amino developing agent is 4-amino-N-ethyl-N-(B-methanesulfonamidoethyl)-m-toluidine sesquisulfate monohydrate.

9. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and 1-(2,4,6-trichlorophenyl)-3-(4-cyanoanilino)-5-pyrazolone.

10. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and 1-(2,4,6-trichlorophenyl)-3-(3- nitroanilino)-5-pyrazolone.

11. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and 1-(2,4,6-trichlorophenyl)-3-(2,4-dichloroanilino) -5-pyrazolone.

12. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and 1-(2,6'-dichloro-4-nitrophenyl)-3- (2,4-dichloroanilino) -5 -pyr az olone.

13. An aqueous alkaline magenta-forming color developer solution containing a primary aromatic amino developing agent and 1-(2,6-dichloro-4-cyanophenyl)-3- (2,4-dichloroanilino) -5-pyrazolone.

14. In a method of producing a magenta photographic image in an exposed silver halide emulsion layer, the step comprising developing said exposed silver halide emulsion layer in the presence of a coupler having the formula:

15. In a process for the color development of an image exposed multilayer, multicolor photographic element comprising a support having coated thereon a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a blue-sensitive silver halide emulsion layer, said process comprising the steps of (1) developing a silver negative image in each of said silver halide emulsion layers,

(2) Washing,

(3) selectively re-exposing the unexposed and undeveloped silver halide in the said redsensitive layer,

(4) cyan color developing the said re-exposed undeveloped silver halide in said red-sensitive layer,

(5) washing (6) selectively re-exposing the unexposed and undeveloped silver halide in the said blue-sensitive layer,

(7) yellow color developing said re-exposed and undeveloped silver halide in said blue-sensitive layer,

(8) washing,

(9) fogging the unexposed and undeveloped silver halide in the green-sensitive silver halide emulsion layer,

(10) magenta color developing the said fogged silver halide,

(11) washing,

(12) bleaching to convert said silver image to silver halide,

(l3) fixing to remove silver halide,

(14) wash and dry,

the improvement comprising the use in the magenta color developing step of an aqueous alkaline solution containing a primary aromatic amino developing agent and a coupler having the formula:

wherein I represents a group selected from the class consisting of the chlorine atom, the nitro group, and the cyano group; W represents a group selected from the class consisting of the hydrogen atom, and the chlorine atom; X represents a group selected from the class consisting of the hydrogen atom, the cyano group, and the nitro group; Y represents a group selected from the class consisting of the hydrogen atom, the chlorine atom, the cyano group and the methylsulfonyl group; Z represents a group selected from the class consisting of the hydrogen atom, and the cyano group, such that at least one of the groups W, X, Y, and Z represents a group other than the hydrogen atom.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CETIFICATE OF CORREQTIQN Patent Noe 3,152,896 October 15, 1964 Robert J. Tuite error appears in the above numbered pat- It is hereby certified that t the said Letters Patent should read as ent requiring correction and the corrected below.

Column 5, lines 35 to 45, for that portion of equation (11) reading CH CH CH read CH CO CH column 5, line -17, for "4000" read 505 line 46, for "container" read contained Signed and sealed this 19th day of April 19660 (SEAL) Attcst: ERNEST W. SER EDWARD J. BRENNER Attesting Officer Commissioner of Patents