DE69118569T2 - Photographic material and method comprising a washable naphthol coupler - Google Patents

Description

This invention relates to a new photographic naphtholic coupler capable of producing a dye by oxidative coupling which can be washed out of the photographic material containing the coupler during development, as well as to photographic materials and a process using the naphtholic coupler.

Various couplers are known in photographic materials and processes. One class of photographic couplers includes naphtholic couplers which typically form cyan dyes upon oxidative coupling in photographic materials and processes. These naphtholic couplers typically form cyan dyes upon oxidative coupling with color developing agents. Naphtholic couplers are also known which are capable of forming dyes by oxidative coupling which can be washed out of the photographic material during development. These naphtholic couplers are described, for example, in U.S. Patent 4,482,629.

The naphtholic couplers capable of forming dyes which can be washed out of the photographic material during photographic processing contain a water-solubilizing group, such as a carboxy group or sulfonic acid group, substituted for a group in the 2-position of the naphtholic coupler. It is desirable to provide naphtholic couplers which are less expensive to produce than the described naphtholic couplers and yet form a suitable dye which can be washed out of the photographic material, with the additional advantage that the coupler enables the use of a lower concentration of coupler in a photographic element without affecting the image formation results. be changed in a significant way.

It would be further desirable to provide such a naphtholic coupler containing a coupling-off group that provides desirable sharpness and interimage effects in a silver halide color photographic material and process at lower coupler concentrations.

The present invention solves this problem by providing a photographic material comprising a support having coated thereon at least one silver halide photographic emulsion layer and wherein in the emulsion layer or in a layer adjacent to the emulsion layer there is an immobile naphthol coupler which upon oxidative coupling forms a dye which can be washed out of the photographic element during photographic processing, the immobile naphthol coupler comprising a ballast-free naphthol coupler moiety having a -CONH₂ group in the 2-position and a ballasted coupling-off group in the 4-position. The ballasted coupling-off group preferably comprises a releasable photographically useful group (PUG).

The immobile naphtholic coupler is typically represented by the formula:

wherein Z is a ballasted coupling-off group, wherein R₁ is a ballast-free substituent which does not adversely affect the desired properties of the coupler and the dye and wherein z is 0, 1, 2 or 3. R₁ does not contain a ballast group since such a group adversely affects the wash-out properties of the dye formed from the naphtholic coupler.

The ballasted coupling-off group (Z) causes the naphtholic coupler to be immobile in the photographic material prior to exposure and processing. Upon exposure and processing of the described element, the naphtholic coupler reacts with oxidized color developing agent to form a dye which is washed out of the element during processing. Also, the coupling-off group is released during processing. The portion of the coupling-off group containing the ballast group remains at the site where it was coated. The coupling-off group preferably comprises a releasable photographically useful group (PUG) which is released upon photographic processing. The PUG group is either immobilized to remain at the site of the element where it was coated or the PUG group is mobile so that after release it can migrate to a location in the element where it can perform its intended function.

A preferred naphtholic coupler as described comprises a coupling-off group represented by the following formula:

-(LINK)n-(TIME)m-PUG

which mean

TIME a releasable timing group that can be released from the LINK residue during photographic development;

LINK a releasable linking group that can be released from the naphtholic coupler moiety upon oxidative coupling of the naphtholic coupler;

n and m individually equal to 0, 1 or 2;

PUG is a releasable photographically useful group, preferably a releasable development inhibitor group; and preferably

at least one of n and m is 1 or 2.

A process for producing an image having the described advantages comprises developing an exposed photographic element as described using a color developing agent in the presence of the described naphtholic coupler and washing out the dye formed from the naphtholic coupler.

Any naphtholic coupler moiety is suitable which contains the -CONH₂ group in the 2-position and a coupling-off group in the 4-position and is capable of producing a compound, especially a dye, which can be washed out of the element upon oxidative coupling of the coupler. It will be appreciated that, depending upon the particular developing agent used and the particular type of development, the reaction product of the coupler moiety and the oxidized developing agent may be colored or colorless. Examples of suitable naphtholic coupler moieties may be unsubstituted except for the required substituents in the 2- and 4-positions as described. Optionally, the naphtholic coupler moieties may contain, in addition to the substituents in the 2- and 4-positions, other substituents which do not adversely affect the desired properties of the element and coupler. Examples of such substituents include 5-NHSO₂CH₃, 5-NHCOCH₃ or 6-NHSO₂CH₃. Useful or suitable naphtholic coupler moieties include those described, for example, in the following patents in which the group described in the 2-position is replaced by the group -CONH₂, particularly those having a ballasted coupling-off group: U.S. Patent Nos. 4,840,884; 4,861,701; 2,474,293; 3,227,554; 4,482,629 and 4,857,447.

Any coupling-off group containing a ballast group known in the photographic art is suitable for the 4-position of the described naphtholic coupler moiety. Examples of suitable coupling-off groups are described, for example, in U.S. Patent 4,861,701. Preferred coupling-off groups are those which allow the release of a PUG group upon photographic processing, particularly those which have a releasable or cleavable timing group between the bond to the coupling position of the coupler and the releasable PUG group. Preferred timing groups are described, for example, in U.S. Patents 4,861,701; 4,248,962; 4,409,323; 4,482,629 and 4,857,447.

A preferred naphtholic coupler is represented by the formula:

which mean

X represents the atoms that complete a 5-, 6- or 7-membered ring, such as an aryl group or a heterocyclic group;

R₁ is a ballast-free substituent;

z is 0, 1, 2 or 3;

BALL a ballast group that is well known in the photographic field;

T² is a releasable timing group;

R₂ and R₃ individually represent hydrogen, unsubstituted or substituted alkyl or aryl, such as alkyl having 1 to 40 carbon atoms or aryl having 6 to 40 carbon atoms, such as for example a phenyl or naphthyl group; and

q is 0, 1 or 2.

For example, T2 is a group that allows release or cleavage of PUG due to intramolecular nucleophilic displacement, as described, for example, in U.S. Patent 4,248,962 and U.S. Patent 4,861,701.

In the case of such couplers which release a PUG group by means of a timing group, the reaction of the coupler with oxidized color developing agent cleaves the bond between the coupler and the coupling-off group. Then the bond between the PUG group and the remainder of the coupling-off group is cleaved. Bond cleavage between the PUG group and the remainder of the coupling-off group preferably does not involve the action of oxidized color developing agent. Cleavage of the bond between the PUG group and the remainder of the coupling-off group may involve any reaction known in the photographic art for cleavage of such groups, for example, an intramolecular nucleophilic displacement reaction or other elimination reaction.

Any ballast group known in the photographic art may be suitable for the coupling-off group. The term ballast group (BALL) as used herein means an organic group of such size and configuration that helps to make the coupler molecule sufficiently bulky to affect the coupler so that it is practically unable to diffuse out of the layer in which it is coated in a photographic element prior to exposure and processing. Representative ballast groups include substituted or unsubstituted alkyl or aryl groups having, for example, 8 to 40 carbon atoms. Other suitable ballast groups include sulfonamido groups having 8 to 40 carbon atoms, carbonamido, carbamoyl, sulfamoyl, ester, sulfone, ether, thioether and amino groups.

A typical timing group T2 is a group that allows the release of a PUG group by intramolecular nucleophilic displacement, as described, for example, in U.S. Patents 4,861,701; 4,857,440; 4,847,185 and 4,248,962.

Illustrative time control groups T² are the following:

and other illustrative groups as described in U.S. Patent 4,857,447.

In the formulas given above, R₄, R�5, R�6, R6a, R₇, R₄, R₁₋, R₁₋, R₁₁, R₁₄, R₁₋, R₁₄, R₁₋, R₁₄, R₁₋, R₁₄, R₁₋, R₁₄, individually represents hydrogen or substituents which do not adversely affect the desired properties of the naphtholic coupler or dye formed, such as unsubstituted or substituted alkyl, for example methyl, ethyl, propyl, n-butyl, t-butyl and eicosyl, or unsubstituted or substituted aryl, such as phenyl or substituted phenyl, and PUG is a releasable photographically useful group. At least one of the described groups on the coupling-off group is a ballast group

The term "naphthol coupler" as used here refers to the entire compound, including the coupler moiety and the coupling-off group. The term "naphthol coupler moiety" as used here refers to the part of the coupler other than the coupling-off group.

The PUG group can be any group typically provided imagewise in a photographic element. The PUG group can be a photographic reagent or a photographic dye. A photographic reagent is herein a moiety which, when released, further reacts with components in the photographic element, such as a development inhibitor, a development accelerator, a bleach inhibitor, a bleach accelerator, a coupler (for example, a competitive coupler, a dye-forming coupler or a development inhibitor-releasing coupler (DIR coupler)), a dye precursor, a dye, a developing agent (for example, a competitive developing agent, a dye-providing developing agent or a silver halide developing agent), a silver complexing agent, a fixing agent, an image toner, a stabilizer, a hardening agent, a tanning agent, a fogging agent, an ultraviolet radiation absorber, an antifogging agent, a nucleating agent, a chemical or spectral sensitizer or a desensitizer.

The PUG group can be present in the coupling-off group in preformed form or it can be present in blocked form or in the form of a precursor. The PUG group can, for example, be a preformed development inhibitor or the development inhibiting function may be blocked by representing the point of attachment to the carbonyl group attached to PUG in the coupling-off group. Other examples are a preformed dye, a dye blocked to shift its absorption, and a leuco dye.

A preferred naphtholic coupler as described is a photographic coupler containing a naphtholic coupler moiety and a PUG group having a heteroatom of Groups VIb or Vb of the Periodic Table of the Elements having a negative valence of 2 or 3 bonded to the carbonyl group of the coupling-off group.

Any couplers known in the photographic art can be used with the described naphtholic couplers and in various positions known in the art in a photographic element. The following is a list of patents and publications describing representative couplers that can be used in combination with the described naphtholic couplers:

I. COUP's

A. Couplers which produce cyan dyes when reacted with oxidized color developing agents are described in such representative patents and publications as: U.S. Patents 2,772,162; 2,895,826; 3,002,836; 3,034,892; 2,474,293; 2,423,730; 2,367,531; 3,041,236; 4,333,999 and the reference "Color couplers - a literature review," published in Agfa-Mitteilungen, Volume III, pages 156-175 (1961).

Preferably, such couplers are phenols and naphthols, which produce blue-green dyes when reacted with oxidized color developing agents.

B. Couplers which produce magenta dyes when reacted with oxidized color developing agent are described in such representative patents and publications as: U.S. Patents 2,600,788; 2,369,489; 2,343,703; 2,311,082; 3,152,896; 3,519,429; 3,062,653; 2,908,573 and in the reference "Color Couplers - a Literature Review" published in Agfa-Mitteilungen, Volume III, pages 126-156 (1961)

Preferably, such couplers are pyrazolones and pyrazolotriazoles, which form magenta dyes upon reaction with oxidized color developing agents.

C. Couplers which form yellow dyes when reacted with oxidized color developing agent are described in such representative patents and publications as: U.S. Patents 2,875,057; 2,407,210; 3,265,506; 2,298,443; 3,048,194; 3,447,928 and in the reference "Color couplers - a literature review" published in Agfa-Mitteilungen, Volume III, pages 112-126 (1961).

Preferably, such couplers are acylacetamides, such as benzoylacetanilides and pivaloylacetanilides, which form yellow dyes upon reaction with oxidized color developing agents.

D. Couplers which form colorless products upon reaction with oxidized color developing agent are described in such representative patents as: U.B. Patent No. 861,138; U.S. Patent Nos. 3,632,345; 3,928,041; 3,958,993 and 3,961,959. Preferably, such couplers are cyclic carbonyl-containing compounds which form colorless products upon reaction with oxidized color developing agent.

Any releasable PUG group known in the photographic art is suitable in the coupling-off group as described. Examples of suitable PUG groups are the following:

PUG's

A. PUG groups which generate development inhibitors upon release are described in such representative patents as U.S. Patent Nos. 3,227,554; 3,384,657; 3,615,506; 3,617,291; 3,733,201; 4,861,701 and U.K. Patent No. 1,450,479. Preferred development inhibitors are iodide and heterocyclic compounds such as mercaptotetrazoles, selenotetrazoles, mercaptobenzothiazoles, selenobenzothiazoles, mercaptobenzoxazoles, selenobenzoxazoles, mercaptobenzimidazoles, selenobenzimidazoles, oxadiazoles, benzotriazoles and benzodiazoles. Structures of preferred development inhibitor moieties are:

wherein R₂�9 is unsubstituted or substituted alkyl, such as butyl, 1-ethylpentyl and 2-ethoxyethyl or alkylthio, such as butylthio and octylthio; R₂₅ and R₂₆ are individually hydrogen, alkyl having 1 to 8 carbon atoms, such as methyl, ethyl or butyl, phenyl or substituted phenyl; and R₂₇ and R₂₈ are individually hydrogen or one or more halogen atoms, such as chloro, fluoro or bromo; Alkyl having 1 to 4 carbon atoms, carboxyl, ester groups such as -COOCH₃, or other substituents such as -NHCOOCH₃, -SO₂OCH₃, -OCH₂CH₂SO₂CH₃, -O OCH₂CH₃₁ -NH OCH₃ or nitro groups.

B. PUG groups that are dyes or form them upon release:

Suitable dyes and dye precursors include azo-, azomethine-, azopyrazolone-, indoaniline-, indophenol-, anthraquinone-, triarylmethane-, alizarin-, nitro-, quinoline-, indigoid- and phthalocyanine dyes or precursors of such dyes such as leuco dyes, tetrazolium salts or shifted dyes. These dyes may be complexed with metals or they may form complexes with metals. Representative patents describing such dyes are U.S. Patent Nos. 3,880,658; 3,931,144; 3,932,380; 3,932,381 and 3,942,987. Preferred dyes and dye precursors are azo, azomethine and indoaniline dyes and dye precursors. Structures of some preferred dyes and dye precursors are:

C. PUG groups that are matchmakers:

The released couplers can be non-diffusing color forming couplers, non-dye forming couplers or diffusing competitive couplers. Representative patents and publications describing competitive couplers are: "On the Chemistry of White Couplers", by W. Püschel, Agfa-Gevaert AG Mitteilungen der Forschungs-Laboratorien der Agfa-Gavaert AG, Springer Verlag, 1954, pages 352-367; US patents 2 998 314; 2 808 329; 2 689 793; 2 742 832; German patent 1 168 769 and British patent 907 274. Structures of preferred competitive couplers are:

wherein R₃₂ is hydrogen or alkylcarbonyl such as acetyl, and wherein R₃₃ and R₃₄ individually are hydrogen or a solubilizing group such as sulfo, aminosulfonyl and carboxy;

wherein R₃₅ has the same meaning as R₃₄ as defined above, and wherein R₃₆ represents halogen, aryloxy, arylthio or a development inhibitor such as a mercaptotetrazole such as phenylmercaptotetrazole or ethylmercaptotetrazole.

D. PUG groups that form developer associations:

Released developing agents can be color developing agents, black and white developing agents or cross-oxidizing developing agents. These include aminophenols, phenylenediamines, hydroquinones and pyrazolidones. Representative patents are U.S. Patents 2,193,015; 2,108,243; 2,592,364; 3,656,950; 3,658,525; 2,751,297; 2,289,367; 2,772,282; 2,743,279; 2,753,256 and 2,304,953.

Structures of preferred developer compounds are:

wherein R₃₇ represents hydrogen or alkyl having 1 to 4 carbon atoms and wherein R₃₈ represents hydrogen or one or more halogen atoms, such as chloro or bromo, or represents alkyl having 1 to 4 carbon atoms, such as methyl, ethyl or butyl groups.

wherein R₃�8 has the meaning given above.

wherein R₃₉ represents hydrogen or alkyl having 1 to 4 carbon atoms and wherein R₄₀, R₄₁, R₄₂, R₄₃ and R₄₄ individually represent hydrogen, alkyl having 1 to 4 carbon atoms, such as methyl or ethyl; hydroxyalkyl having 1 to 4 carbon atoms, such as hydroxymethyl or hydroxyethyl, or sulfoalkyl having 1 to 4 carbon atoms.

E. PUG groups which are bleach inhibitors:

Representative patents are US patents 3,705,801 and 3,715,208 and German OLS 2,405,279. Structures of preferred bleach inhibitors are:

wherein R₄₅ represents an alkyl group having 6 to 20 carbon atoms.

F. PUG groups that are bleaching accelerators:

wherein R₄₆ is hydrogen, alkyl, such as ethyl and butyl, alkoxy, for example ethoxy and butoxy, or alkylthio, such as ethylthio and butylthio, having, for example, 1 to 6 carbon atoms, and which may be unsubstituted or substituted; wherein R₄₇ is hydrogen, alkyl or aryl, such as phenyl; wherein R₄₈ and R₄₉ are individually alkyl, such as alkyl having 1 to 6 carbon atoms, for example ethyl and butyl; and wherein z is 1 to 6.

The image dye-forming couplers can be incorporated into photographic elements and/or used in photographic processing solutions, such as developer solutions, so that when an exposed photographic element is processed, they enter into reactive association with oxidized color developing agent. Coupler compounds incorporated into photographic processing solutions should be of a molecular size and configuration such that they can diffuse with the processing solution through photographic layers. When incorporated into a photographic element, as a general rule, the coupler compounds should be non-diffusible such that they are of a molecular size and configuration such that they do not substantially diffuse or migrate from the layer in which they are coated.

Photographic elements of this invention can be processed by conventional techniques in which color forming couplers and color developing agents are used in separate processing solutions or compositions or in the element.

Photographic elements in which the compounds of this invention are used can be simple elements comprising a support and a single silver halide emulsion layer or they can be multilayer, multicolor elements. The compounds of this invention can be incorporated into at least one of the silver halide emulsion layers and/or into at least one other layer, such as an adjacent layer from where they can enter into reactive association with oxidized color developing agent which has developed silver halide in the emulsion layer. The silver halide emulsion layer may contain or may have associated therewith other photographic coupler compounds such as dye-forming couplers, colored masking couplers and/or competitive couplers. These other photographic couplers may provide dyes of the same or different color or hue as the photographic couplers of this invention. In addition, the silver halide emulsion layers and other layers of the photographic element may contain addenda conventionally included in such layers.

A typical multilayer, multicolor photographic element may comprise a support having disposed thereon a red-sensitive silver halide emulsion unit having associated therewith a cyan dye image-forming material, a green-sensitive silver halide emulsion unit having associated therewith a magenta dye image-forming material, and a blue-sensitive silver halide emulsion unit having associated therewith a yellow dye image-forming material, with at least one of the silver halide emulsion units having associated therewith a photographic coupler of the invention. Each silver halide emulsion unit may be constructed of one or more layers, and the various units and layers may be disposed in different positions relative to one another.

The couplers of this invention can be incorporated into or associated with one or more of the layers or units of the photographic element. For example, a layer or unit affected by PUG can be controlled by introducing, at appropriate positions in the element, a scavenger layer which inhibits the action of PUG on the desired layer or unit. unit. At least one of the layers of the photographic element can be, for example, a mordant layer or a release layer.

The light-sensitive silver halide emulsions may contain coarse, regular or fine grain silver halide crystals or mixtures thereof and may be composed of such silver halides as silver chloride, silver bromide, silver bromoiodide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide and mixtures thereof. The emulsions may be negative-working or direct-positive-working emulsions. They may form latent images predominantly on the surface of the silver halide grains or predominantly in the interior of the silver halide grains. They may be chemically and spectrally sensitized. The emulsions are typically gelatin emulsions, although other hydrophilic colloids are suitable. Tabular photosensitive silver halide grains are particularly suitable, for example those described in Research Disclosure, January 1983, Item 22534 and in U.S. Patent 4,434,226.

The support can be any support used to make photographic elements. Typical supports include cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polyethylene terephthalate film, polycarbonate film and similar films or resinous materials, as well as glass, paper, metal and the like. Typically a flexible support is used, such as a polymer film or a paper support. Paper supports can be acetylated or coated with a baryta layer and/or an alpha-olefin polymer, particularly a polymer of an alpha-olefin having 2 to 10 carbon atoms, such as polyethylene, polypropylene, ethylene-butene copolymers and the like.

Preferably, the coupling-off group contains a releasable PUG group. Depending on the nature of the specific PUG group, the couplers are inserted or placed in a photographic element for different purposes and at different locations.

In the following discussion of suitable materials for use in the emulsions and elements of this invention, reference is made to Research Disclosure, December 1978, No. 17643, published by Industrial Opportunities Ltd., Homewell Havant, Hampshire, P09 1EF, United Kingdom. This reference is hereinafter referred to as "Research Disclosure."

The photographic elements can be prepared by coating using a variety of supports as described in Research Disclosure, Section XVII and the references cited therein.

Photographic elements can be exposed to actinic radiation, typically actinic radiation in the visible region of the spectrum, to form a latent image as described in Research Disclosure, Section XVIII, and then the elements are processed to form a visible dye image as described in Research Disclosure, Section XIX. Processing to form a visible dye image includes the step of contacting the element with a color developing agent to reduce developable silver halide and oxidize the color developing agent. Oxidized color developing agent then reacts with the coupler to form a dye.

Preferred color developing agents which can be used according to the invention are p-phenylenediamines. Particularly preferred are 4-amino-N,N-diethylaniline hydrochloride; 4-amino-3-methyl-N,N-diethylaniline hydrochloride; 4-Amino-3-methyl-N-ethyl- N-β-(methanesulfonamido)ethylaniline sulfate hydrate; 4-Amino-3-methyl-N-ethyl-N-β-hydroxyethylaniline sulfate; 4-Amino-3-β-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride; and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine-di-p-toluenesulfonic acid.

When negative-working silver halide is used, the development step described above produces a negative image. To obtain a positive (or reversal) image, this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide but without producing a dye, and then the element is uniformly fogged to render unexposed silver halide developable. Alternatively, a direct-positive emulsion can be used to produce a positive image.

Development is followed by the usual steps of bleaching, fixing or bleach-fixing to remove silver and silver halide, washing and drying.

Naphtholic couplers as described can be prepared by reactions and methods known in the art of organic compound synthesis. Relevant reactions and methods are described in U.S. Patent No. 4,482,629. Typically, the naphtholic coupler is prepared by the following method: Synthesis A: Pyridine Pyridine Ph stands for phenyl.

Synthesis example A : - Compound (A2):

Phenyl 1,4-dihydroxy-2-naphthoate (100.0 g, 356.78 mmol) was dissolved in deoxygenated tetrahydrofuran (500 mL) and deoxygenated methanol (500 mL) was added. To this solution, which was stirred at room temperature under a nitrogen atmosphere, was added ammonium acetate (50.0 g, 648.63 mmol) followed by concentrated ammonium hydroxide (1.0 L). After stirring for 3 h, the reaction mixture was poured into ice-cold 2 N HCl (4.0 L) and sufficient concentrated HCl was added to bring the pH to 1. The resulting product, compound (A2), was filtered off, washed thoroughly with water and air dried. The crude product was washed with dichloromethane and air dried. The yield was 62.0 g (72%).

Connection (A3):

Compound (A2) (50.0 g, 0.246 mol) was dissolved in dry pyridine (150 mL) and acetonitrile (75 mL) was added. The solution was stirred and cooled to -5 to 0 °C. Then ethyl chloroformate (50 mL, 0.523 mol) was added dropwise with stirring while maintaining the temperature at 0 °C. After the addition, the bath used for cooling was removed and the temperature was allowed to rise to room temperature. The reaction mixture was then gradually heated to reflux temperature and the solvent was distilled off. This procedure was continued until the temperature had risen to about 120 °C and 150 mL of solvent had been collected. Heating under reflux conditions was continued for an additional period of one hour. The reaction mixture was then cooled to about 50 °C and poured into 2 N HCl (3.0 L) which was maintained at room temperature. This suspension was then stirred for approximately 15 minutes, filtered and the residue was thoroughly with water, acetonitrile and finally with ether. This gave the product, compound (A3), in sufficient purity for the next step. The yield was 43.5 g (77%).

Connection (A4):

Compound (A3) (23.0 g, 100.35 mmol) was taken up in deoxygenated dimethyl sulfoxide (250 mL) and deoxygenated water (25 mL) was added. To this solution, which was stirred at room temperature under nitrogen, 85% potassium hydroxide (9.9 g, 150.53 mmol) was added and stirring was continued until dissolution occurred, which took approximately 15 minutes. Then 4-chloro-3-nitrobenzaldehyde (18.63 mmol) was added in one portion and the resulting solution was stirred at 60 °C for one hour. The reaction mixture was then poured into ice-cold 2 N HCl (2.0 L) and filtered. The product, compound (A4), was washed with water and suspended in methanol while still wet, filtered and washed with ether. This product was pure enough to be used in the next step. Yield 28.0 g (74%).

Connection (A5):

Compound (A4) (28.0 g, 74.01 mmol) in powder form was suspended in tetrahydrofuran (150 mL) and methanol (100 mL). Water (100 mL) was added followed by sodium borohydride (2.8 g, 74.01 mmol) in small portions. Additional tetrahydrofuran (50 mL) was added to facilitate stirring. At the end of the sodium borohydride addition, complete dissolution was achieved. The reaction was allowed to proceed for an additional 15 minutes, after which the mixture was poured into ice-cold 2 N HCl (2.0 L) and the product was filtered off. The product, compound (AS), was washed with methanol while still wet with the solvent, suspended in ethanol and heated to reflux temperature. The solution was cooled, filtered, washed with methanol and ether and finally dried in air. A second crop of material was obtained by concentrating the mother liquor. The overall yield was 19.5 g (67%).

Connection (A6):

Compound (A5) (19.0 g, 50 mmol) was suspended in water (200 mL) containing 85% potassium hydroxide (26.34 g, 400 mmol). To this mixture was added methanol (50 mL) followed by heating at 80 °C for 1 h. The resulting dark yellow-brown solution was cooled and poured into ice-cold 2 N HCl (2.0 L). The yellow product was filtered off, washed thoroughly with water and air dried. Yield 17.7 g (100%).

Connection (A7):

Compound (A6) (17.7 g, 70 mmol) was dissolved in tetrahydrofuran (80 mL) and methanol (300 mL) was added. Raney nickel, which had been washed several times with water and then with methanol, was added and the solution was hydrogenated at 55 psi for 2 h, after which hydrogen uptake was complete. The catalyst was filtered off, washed with methanol, and the filtrate was concentrated under reduced pressure to give the product, compound (A7). This product was considered sufficiently pure to carry to the next step. Yield 100%.

Connection (A8):

Compound (A7) (50.0 mmol) was dissolved in dry pyridine (150 mL) and hexadecylsulfonyl chloride (16.2 g, 50.0 mmol) was added. The solution was stirred at room temperature under a nitrogen atmosphere for 30 min. The pyridine was concentrated at reduced pressure and the residue was taken up in ethyl acetate. This ethyl acetate solution was then washed with 2N-HCl (X3), dried (MgSO4), filtered and concentrated. The solvent was removed at reduced pressure and the residual oil was purified from acetonitrile. crystallized. After filtration, washing with acetonitrile and drying, the yield of the product of compound (A8) was 16.3 g (53% calculated from compound (A5)).

Connection (A9):

Compound (A8) (16.3 g, 26.6 mmol) was dissolved in tetrahydrofuran (150 mL) to which pyridine (3.2 mL, 39.90 mmol) and then chloroacetic anhydride (6.82 g, 39.89 mmol) in tetrahydrofuran (30 mL) were added at an appropriately high rate. After stirring at room temperature for 30 min, the solvent was removed under reduced pressure and the residue was dissolved in ethyl acetate. The ethyl acetate solution was then washed with 2N-HCl (X2), dried (MgSO4) and concentrated under reduced pressure. The residue crystallized from acetonitrile to give compound (A9) 12.2 g (66%).

Connection (A10):

Compound (A9) (12.2 g, 17.7 mmol) was dissolved in dimethylformamide (150 mL) to which potassium iodide (4.4 g, 25.55 mmol) and aniline (8.2 mL, 88.5 mmol) had been added, and the reaction mixture was heated at 60 °C for 1.5 h. The reaction mixture was poured into 2 N-HCl and extracted with ethyl acetate (X2). The combined ethyl acetate extracts were washed with 2 N-HCl (X3), dried (MgSO4), filtered and then concentrated. The residue was used as such in the next step of the reaction sequence, but it could be recrystallized from acetonitrile. The yield was assumed to be 100%.

Connection (A11):

The compound (A10) (83.0 g, 111.26 mmol) was dissolved in tetrahydrofuran (800 mL) and the solution was stirred at room temperature. N,N-4-diethylaniline (17.7 mL, 111.26 mmol) was added, followed by the addition of a solution of 12% phosgene in toluene (275 mL, 333.78 mmol). The reaction mixture was stirred at Stirred at room temperature for 15 minutes, concentrated under reduced pressure and the residue was used as such in the next step. The yield of the product, compound (A11), was taken as 100%.

Connection (A12):

Compound (A11) as described above (111.26 mmol) was dissolved in dry pyridine (800 mL) and PMT (19.83 g, 111.26 mmol) was added to the reaction solution. The mixture was stirred at room temperature for 1 h. It was then concentrated under reduced pressure and the residue was taken up in ethyl acetate. The ethyl acetate was washed with 2N-HCl (X3), dried (MgSO4), filtered and concentrated to an oil. The oil was taken up in a mixture of ethyl acetate, dichloromethane, heptane and acetonitrile in a ratio of 20:20:56:4 and subjected to flash chromatography, eluting with the same solvent system to elute impurities from the column, after which the ratio was changed to 27:50:20:4 to elute the product, compound (A12). The product could be recrystallized from acetonitrile. Yield 61.0 g (58%).

Calculated for C₅₀�0₁H₅�9₁N₇O₄S₂:

% C = 63.20, % H = 6.26, % N = 10.32, % S = 6.75

found: % C = 63.14, % H = 6.29, % N = 10.23, % S = 6.62

Connection (A13):

Compound (A8) (4.0 g, 6.53 mmol) was suspended in dry ether (30 mL) and phosphorus tribromide (0.68 mL, 7.18 mmol) in ether (20 mL) was added dropwise over a period of 15 minutes. After the addition, the reaction mixture was diluted with ether and the ether solution was washed with 2 N-HCl (X1), dried (MgSO4), filtered and concentrated to give compound (A13). The yield was 100%.

Connection (A14):

Compound (A13) (6.53 mmol) was dissolved in dimethylformamide (40 mL) to which PMT (1.51 g, 7.54 mmol) had previously been added and the resulting mixture was stirred at room temperature for 1 hour. Compound (A14) was isolated by pouring the reaction mixture into 2 N HCl and extracting with ethyl acetate (X2). The combined ethyl acetate extracts were then washed with 2 N HCl (X3), dried (MgSO4), filtered and concentrated. The residue was taken up in a mixture of ethyl acetate, heptane and dichloromethane in a ratio of 15:30:5 and the product was subjected to flash chromatography eluting with the same solvent mixture. The first major band was separated to give the product. Yield 4.0 g (79%).

Calculated for C₄₁₁H₅₂N₆O₅S₂:

% C = 63.70, % H = 6.78, % N = 10.87, % S = 8.30

found: % C = 63.40, % H = 6.80, % N = 10.76, % S = 8.14 PMT here means phenylmercaptotetrazole.

Synthesis example B : - Compound (B16):

Compound (A3) (3.4 g, 14.83 mmol) was dissolved in deoxygenated dimethyl sulfoxide (100 mL) and stirred at room temperature under a nitrogen atmosphere. To this solution was added 85% potassium hydroxide (1.71 g, 25.95 mmol), followed by deoxygenated water (10 mL). The reaction mixture was stirred at room temperature for 15 min, after which benzophenone (B15) (7.0 g, 14.83 mmol) was added as a solid in a single batch. The dark colored solution was then heated to 60 °C and stirring was continued for an additional 2.5 h. While still at 60 °C, the warm solution was poured into ice-cold 2 N HCl (600 mL). The yellow product was filtered off, with water and then with methanol and dried in air. The yield of compound (B16) was 8.8 g (89%).

Connection (B17):

Compound (B16) (8.8 g, 13.24 mmol) was dissolved in tetrahydrofuran (40 mL) to which methanol (20 mL) and water (20 mL) had been added. Sodium borohydride (0.5 g, 13.24 mmol) was added portionwise to the suspension with stirring. At the end of the addition, the dissolution was complete and the solution was continuously stirred for an additional 15 minutes. The reaction solution was then poured into ice-cold 2 N HCl (600 mL) and the product compound (B17) was filtered, washed with water, methanol and air dried. The yield was 7.9 g (89%).

Connection (B18):

Compound (B17) (10.0 g, 15.0 mmol) was suspended in water (70 mL) and 85% potassium hydroxide (7.90 g, 120.0 mmol) was added along with methanol (20 mL). The mixture was stirred at 80 °C for 1 h, cooled and poured into ice-cold 2 N HCl and the mixture was extracted with ethyl acetate (X2). The combined ethyl acetate extracts were then dried (MgSO4), filtered and concentrated. The residual compound (B18) was used as such in the next step of the reaction sequence. Yield (100%).

Connection (B19):

Compound (B18) (15 mmol) was dissolved in ether (70 mL) and phosphorus tribromide (1.6 mL, 16.5 mmol) in ether (15 mL) was added dropwise over a period of 15 minutes. After completion of the addition, the reaction solution was stirred at room temperature for an additional 15 minutes. The solution was then diluted with ether, washed with 2N-HCl (X3), dried (MgSO4), filtered and concentrated under reduced pressure. This gave compound (B19) in sufficient purity to be used in the next step. Yield 100%.

Connection (B20):

Compound (B19) (15.0 mmol) was dissolved in dimethylformamide (50 mL) and treated with sodium PMT (3.55 g, 17.73 mmol) with stirring at room temperature for 1 hour. The reaction solution was then diluted with ethyl acetate and washed with 2N HCl (X4). The organic layer was then dried (MgSO4), filtered and concentrated under reduced pressure. The oil was dissolved in 25% ethyl acetate in heptane and the solution was subjected to flash chromatography, eluting with the same solvent mixture. The first major band was separated to give the product compound (B20). Yield 5.0 g [42% from compound (B17)].

Calculated for C₄₆H₅₂N₆O₅S:

% C = 68.98, % H = 6.54, % N = 10.49, % S = 4.00

found: % C = 69.07, % H = 6.44, % N = 10.31, % S = 4.12

Couplers that can be prepared using these synthesis methods include: Connection number Connection number Connection number Connection number Connection number Connection number Connection number Connection number

The following examples are intended to further illustrate the invention:

Examples 1 -3:

Photographic elements were prepared by coating the following layers on a cellulose ester film support (amounts of each compound are given in mg/m²):

Emulsion layer 1:

Gelatin - 2420; red-sensitized silver bromoiodide (as Ag) - 1615; yellow image coupler dispersed in dibutyl phthalate (RECEIVING LAYER)

Intermediate layer:

Gelatin - 860; Didodecylhydroquinone- 113

Emulsion layer 2:

Gelatin - 2690; green-sensitized silver bromoiodide (as Ag) - 1615; magenta image coupler dispersed in tritolyl phosphate; DIR compound of Table 1 dispersed in N,N-diethyldodecanamide and coated in an amount sufficient to produce a contrast of 0.5 (half) of the original contrast after gradual exposure to green light and development (CAUSER LAYER)

Protective top layer:

Gelatin - 5380; Bisvinylsulfonylmethylether in an amount of 2% based on the total gelatin

The structures of the image couplers were as follows Purple image coupler: Yellow image coupler

Strips of each element were exposed to green light through a graduated density tray or through a 35% modulation strip card for sharpness measurements, then the strips were developed for 3.25 minutes at 38ºC in the following color developer, treated with a stopper bath, washed, bleached, fixed, washed and dried.

Color developer:

distilled water 800 ml

Sodium metabisulfite 2.78 g

Sodium sulphite, anhydrous 0.38 g

CD-4* 4.52g

Potassium carbonate, anhydrous 34.3 g

Potassium bicarbonate 2.32 g

Sodium bromide 1.31 g

Potassium iodide 1.20 mg

Hydroxylamine sulfate (HAS) 2.41 g

Diethylenetriaminepentaacetic acid, pentasodium salt (40% solution) 8.43 g

distilled water, filled up to 1 l

pH value adjusted to 10.0.

*CD-4 is 4-amino-3-methyl-N-ethyl-N-beta-hydroxyethylaniline sulfate.

Developed images were read with green light to determine contrast and AMT sharpness. From plots of AMT sharpness versus the logarithm of contrast for variations in the coverage of each development inhibitor releasing compound (DIR), sharpness was determined at a contrast of 0.5 compared to its original contrast without the presence of the DIR compound. The sharpness of the control DIR coupler was subtracted from each AMT value to obtain the relative sharpness value, which is given in Table I as the change in AMT. The AMT calculations used the following formula, in which the cascaded area under the system modulation curve is given in equation (21.104) on page 629 of the book "Theory of the Photographic Process", 4th edition, 1977, edited by TH James: AMT = 100+66 Log [cascaded area/2.6696M], where the magnification factor M in the case of the 35 mm system AMT is 3.8. The use of CMT sharpness is described by RG Gendron in "AN Improved Objective Method of Rating Picture Sharpness: CMT acutance" in the Journal of SMPTE, Volume 82, pages 1009-12 (1973). AMT is a further modification of CMT, suitable for the study of systems that involve the observation of a positive print made from a negative. TABLE I Example No. Coupler No. Change in AMT Gamma Source Gamma Receiver Comparative Coupler Comparison coupler: Matchmaker 1 Matchmaker 2 Coupler 3

Compared to the comparison couplers, the couplers of Examples 1-3 lead to improved sharpness and improved interimage effects.

Example 4:

Photographic film was prepared, exposed and developed as described in Examples 1-3. The developed images were examined with green light to determine contrast. From plots of the logarithm of contrast versus the amount of each DIR coupler applied, reactivity was determined as the amount of DIR coupler in micromoles per square meter to reduce the contrast (gamma) to half (0.5) compared to the original contrast without the presence of the DIR coupler. The smaller the amount of DIR compound required, the higher the reactivity of the DIR coupler. Coupler 3 was the same as the coupler described in Example 3. The results are summarized in Table II below: TABLE II Example No. Coupler No. Amount of DIR coupler to reduce gamma by half (micromoles/m²) Coupler C Coupler D

Claims (8)

1. Photographic silver halide material comprising a support on which there is at least one photographic silver halide emulsion layer and in or adjacent to the emulsion layer an immobile naphtholic coupler which is capable of producing a dye by oxidative coupling which can be washed out of the photographic element during photographic development, the immobile naphtholic coupler comprising a ballast-free naphtholic coupler residue having a -CONH₂ group in the 2-position and a ballasted coupling-off group in the 4-position. 2. Photographic material according to claim 1, in which the immobile naphtholic coupler is represented by the formula: wherein Z is a ballasted coupling-off group; R1 is an unballasted substituent and z is 0, 1, 2 or 3. 3. Photographic material according to claim 1, in which the coupling-off group is represented by the formula: where: TIME a releasable timing group which can be released from the LINK residue during photographic development of the element; LINK a timing group that can be released from the naphtholic coupler moiety by oxidative coupling of the naphtholic coupler; n and m are each equal to 0, 1 or 2; PUG a releasable, photographically useful group; and at least one of n and m is equal to 1 or 2. 4. A photographic material according to claim 1, wherein the naphtholic coupler has the following formula: wherein X represents the atoms that complete a 5-, 6- or 7-membered ring, such as an aryl group or a heterocyclic group; and wherein: BALL a ballast group; T² is a releasable timing group; R₂ and R₃ are each individually hydrogen, unsubstituted or substituted alkyl or aryl; q is 0, 1 or 2; and PUG a releasable photographically useful group. 5. A photographic material according to claim 1, wherein the naphtholic coupler has the formula: 6. A photographic material according to claim 1, wherein the ballasted coupling-off group comprises a releasable photographically useful group which is a releasable development inhibitor, developing agent, development accelerator, bleach inhibitor, bleach accelerator, dye, dye precursor, stabilizer, coupler, nucleating agent, fixing agent, image toner, hardener, antifoggant or ultraviolet radiation absorber, said group being directly or indirectly bonded to the coupling position of the naphtholic coupler moiety. 7. A process for producing a photographic image in an exposed photographic material according to any one of claims 1-6, which process comprises developing the exposed silver halide photographic material with a color developing agent. 8. Photographic naphtholic coupler according to one of claims 1-6.