This application is a continuation-in-part of parent application Serial No. 07/343,981, which is hereby incorporated in its entirety by reference.

Background of the Invention

This invention relates to a new blocked photographically useful compound that is capable of more rapidly releasing the photographically useful group of the compound upon reaction of the compound with a dinucleophile reagent. In particular, the invention relates to a new blocked filter dye.

Various compounds, such as couplers and dyes, are known in the photographic art that contain a blocking group and that are capable of being released or unblocked upon processing of the photographic material containing the compound. Such compounds and various blocking groups have been described in, for example, U.S. Patents 4,690,885; 4,358,525 and 4,554,243. While these compounds have enabled increased storage stability compared to compounds that are not blocked and have provided release of the photographically useful group from the compound upon processing, often the stability of the compounds during storage prior to exposure and processing of the photographic materials containing the compounds has not been entirely satisfactory and the rate of release or unblocking of the compound has been less than desired.

Filter dyes are used in a variety of photographic products to absorb unwanted light. For instance, a yellow filter dye or colloidal yellow silver (also known as Carey Lea Silver, or CLS) may be placed between the blue and green light-sensitive layers to filter out unwanted blue light and prevent exposure of the green layer. They may be used in antihalation layers to absorb light reflected, for instance, from the support, which would lead to undesired exposure of light-sensitive layers. They may also be used within light-sensitive layers as intergrain absorbers to enhance sharpness by absorbing light reflected from grains of silver halide. These dyes are generally removed during the development process, either by washing out or by reacting with processing chemicals to be decolorized or otherwise destroyed.

Most of the known filter dyes and CLS technologies, however, have disadvantages. For instance, CLS has significant unwanted green absorption. It also undergoes solution physical development in areas of low exposure with production of dye from image couplers (usually magenta) , which is undesirable. Filter dyes incorporated as solid particle dispersions are sensitive to the surfactant used in coating and are more unpredictable in hue than dyes in solution. Mordantable filter dyes are often not completely immobilized and diffuse into layers where their presence is not desired. Hydrophobic latex loaded filter dyes may not be completely removed during the process, which results

in stains. It would be highly desirable not only to avoid these problems, but also to incorporate the filter dyes as coupler solvent solutions where their hue and curve shape could be accurately predicted and controlled by molecular structure.

This can be achieved by use of filter dye moieties which are immobilized prior to processing by attachment to a blocking group and are made mobile or diffusible during the process by cleavage from the blocking group. The diffusible filter dye moiety released by unblocking can be washed out of the film or be destroyed by the water-soluble nucleophiles such as hydroxide and sulfite in the processing solution. The blocking group is effectively immobilized by ballasting either the blocking group itself or the timing group (or timing groups) which may be used to connect the dye moiety to the blocking group.

Development and application of such blocked filter dyes has depended on the development of practical blocking groups which are stable during storage and which release or unblock the photographically useful group (FUG), e.g., the filter dye, readily during processing. Since many of the blocking groups known in the photographic art do not provide both adeguate storage stability prior to exposure and adeguate rate of release or unblocking during processing, there has been a need for a blocked photographically useful compound containing a blocking group that enables increased storage stability in a

photographic material and enables increased rate of release or unblocking during processing of the photographic material containing such a compound. In particular, a need has existed for a blocked filter dye which avoids the problems associated with known filter dyes.

Summary of the Invention The present invention solves these problems by providing a photographic element comprising a support bearing at least one photographic silver halide emulsion layer and a blocked photographically useful compound comprising a photographically useful group (PUG) , in particular a filter dye, and a new blocking group that is capable of releasing the PUG upon processing the photographic element wherein the blocking group (a) comprises two electrophilic groups, the least electrophilic of which is bonded directly or through a timing group to the photographically useful group (PUG) , and (b) is capable of reacting with a dinucleophile; and wherein (c) the two electrophilic groups are separated from each other by a bond or unsubstituted or substituted atom that enables a nucleophilic displacement reaction to occur with release of the PUG upon processing the photographic element in the presence of a dinucleophile reagent.

A preferred blocked photographically useful compound as described is represented by the formula:

[ E, -(-Y ¹ -).- E ₂ - (T,), - (T ₂ ) _y ] ₀ - PUG

wherein El and E2 are independently electrophilic groups, wherein El is more electrophilic than E2; Tl and T2 are individually releasable timing groups; Yl is an unsubs ituted or substituted atom, preferably a carbon or nitrogen atom, that provides a distance between El and E2 that enables a nucleophilic displacement reaction to occur with release of the PUG upon processing a photographic element containing the blocked photographically useful compound in the presence of a dinucleophile;

PUG is a photographically useful group capable of being released upon processing the photographically useful compound; w, x and y are independently 0 or 1; and n is 1 or 2. An illustrative blocked photographically useful compound within the above formula is represented by the formula:

wherein

R ₃ is. unsubstituted or substituted C(l-

4)alkyl, unsubstituted or substituted aryl, unsubstituted or substituted aralkyl, unsubstituted or substituted alkaryl, unsubstituted or substituted alkoxyaryl, a ballast group, or the atoms necessary with Z to complete a ring with Y ² , Z represents the atoms necessary to complete a ring with R ₃ and Y ² ,

Y ² is a substituted or unsubstituted carbon or nitrogen atom that provides a distance between the carbonyl groups that enables a nucleophilic displacement reaction to occur upon processing a photographic element containing the blocked photographically useful compound in the presence of a dinucleophile, g is 0 or 1, z is an integer from 0 to 3,

T3 is a releasable timing group which is unballasted or ballasted, and

PUG is a photographically useful group, in particular a filter dye. Highly preferred blocked photographically useful compounds are represented by the formulas:

and

wherein

Pv, and R^ individually are unsubstituted or substituted C(l-4)alkyl, unsubstituted or substituted aryl, unsubstituted or substituted aralkyl, unsubstituted or

substituted alkaryl, unsubstituted or substituted alkoxyaryl, or a ballast group, _4t and R^ individually are unsubstituted or substituted C(1-4)alkyl, unsubstituted or substituted aryl, or a ballast group, PUG is a filter dye,

T ₄ and T ₅ are individually releasable timing groups which are unballasted or ballasted, and r and s individually are 0 or 1.

In a preferred embodiment, R ₄ , R _4i , R _4b and R^ are methyl- In another preferred embodiment, R, and R _4c individually are ballast groups as described above. Ballast groups, i.e., groups that decrease the rate of diffusion, are known per se. Exemplary ballast groups are described, e.g., in U.S. Patent No. 4,923,789, col. 7, which is incorporated by reference. The ballast groups R _< according to the instant invention preferably are long-chain unsubstituted alkyl groups, e.g., those having 5 to 40 carbon atoms, aralkyl groups, alkaryl groups, or alkoxyaryl groups in which the aryl moiety can be unsubstituted or substituted. The ballast groups R^ preferably are alkyl or alkaryl groups, which can be further modified, e.g., by the substitution of a sulfonamide (-NHS0 ₂ -) group for a -CH ₂ - group which is not adjacent to the carbonyl group. A preferred R^ ballast group is a benzyl sulfonamide group.

The inventive filter dyes, which are attached to process-cleavable ballasts, provide advantages over the known filter dyes and can be used in a conventional coupler solvent dispersion formulation. The term "process cleavable ballast" denotes a ballast group that is attached to the timing group or blocking group, and that is removed from the PUG, here the filter dye, as a function of the deblocking process. One embodiment of the invention is a photographic element comprising a blocked photographically useful compound, in particular a filter dye, containing the new blocking group as described. Another embodiment is a process of forming a photographic image by developing an exposed photographic element as described in the presence of a dinucleophile reagent. A further embodiment is a new photographically useful compound, in particular a filter dye, containing the new blocking group as described.

Brief Description of the Drawing

The invention may be more readily understood by referring to the accompanying drawing by which

FIG. 1 is a plot of density vs. wavelength for filter dyes according to the invention compared to CLS.

Deta led Description of the Preferred Embodiments

The blocked photographically useful compounds enable both improved storage stability and more rapid release upon processing of a photographic element containing such a compound- Both of these properties are achieved by the blocked photographically useful compounds as described due at least in part to the particular structure of the new blocking group. In the past it was possible for blocked photographically useful compounds to react with nucleophilic compounds containing one nucleophilic group, such as methylamine, hydroxide or water, that help reduce storage stability of the photographic element containing such compounds. The blocked photographically useful compounds of the invention do not release the photographically useful groups of the compound upon reaction with a nucleophilic compound containing only one nucleophilic group. Rather, release occurs only upon reaction with a nucleophilic compound containing two nucleophile groups, described herein as a dinucleophile reagent, such as hydroxylamines, hydrogen peroxide, hydrazine, diamines and substituted hydrazines. Carbonyl groups are preferred electrophilic groups in the new blocking groups as described.

The new blocking group structure resists reaction with nucleophilic compounds containing only one nucleophilic group. For example, reaction of a nucleophilic compound containing only one

nucleophilic group at El in the case of a carbonyl group would lead to adducts in which the hydroxyl group generated can internally react with E2 only by a three or four member ring that is very difficult to form. In most cases, only compounds, such as water, that contain one nucleophilic group are encountered in storage of photographic silver halide elements. Such compounds would not release the blocking group of the invention as described. In chemical systems reguiring the good storage properties and the more rapid release properties of the compounds as described, the release of the blocking group can be initiated by reaction of the blocking group with an appropriate dinucleophile reagent. The selection of an appropriate dinucleophile reagent preferably enables formation of a five- or six-member ring compound. Depending upon the particular photographically useful group, the particular blocking group and the desired end use of the compound, the initiation of deblocking can take place by reacting the particular dinucleophile reagent at concentrations and under conditions that enable the desired rate of release. The dinucleophile herein means a compound represented by the formula:

HNu, - X ¹ - Nu ₂ H

wherein

Nul and Nu2 individually are nucleophilic N, 0, S, P, Se, substituted nitrogen atoms, or substituted carbon atoms, and

X ¹ is a chain of j atoms wherein j is 0, 1 or 2. Illustrative examples of useful dinucleophile reagents are as follows:

Preferred dinucleophile reagents are hydroxylaπine , hydrogen peroxide, and monosubstituted hydroxylamine. The dinucleophile reagent herein also includes a salt form of the reagent, such as the acid salts, for example, sulfate or bisulfite salts.

As used herein the term photographically useful group (PUG) refers to any group that can be used in a photographic material and that can be released from the blocking group as described- It refers to the part of the blocked photographically

useful compound other than the blocking group. The PUG can be, for example, a photographic dye, which can be diffusible or non-diffusible, or a photographic reagent. A photographic reagent herein is a moiety that upon release further reacts with components in the photographic element. Such photographically useful groups include, for example, couplers (such as, image dye-forming couplers, development inhibitor releasing couplers, competing couplers, polymeric couplers and other forms of couplers) , development inhibitors, bleach accelerators, bleach inhibitors, inhibitor releasing developers, dye precursors, developing agents (such as competing developing agents, dye-forming developing agents, developing agent precursors, and silver halide developing agents) , silver ion fixing agents, silver halide solvents, silver halide complexing agents, image toners, pre-processing and post-processing image stabilizers, hardeners, tanning agents, fogging agents, antifoggants, ultraviolet radiation absorbers, nucleators, chemical and spectral sensitizers or desensitizers, surfactants, and precursors thereof and other addenda known to be useful in photographic materials.

The PUG can be present in the photographically useful compound as a preformed species or as a precursor- For example, a preformed development inhibitor may be bonded to the blocking group or the development inhibitor may be attached to a timing group that is released at a particular

ti e and location in the photographic material. The PUG may be, for example, a preformed dye or a compound that forms a dye after release from the blocking group. In a preferred embodiment, PUG is a filter dye.

The photographically useful compound can optionally contain at least one releasable timing group (T) between the PUG and the blocking group as described. The reaction of the photographically useful compound with a dinucleophile reagent can seguentially release the blocking group from the timing group and then the timing group can be released from the PUG. The term "timing group" herein also includes a linking group that involves little or no observable time in the release action. This can occur in, for example, the development step of an exposed photographic element when the developer composition comprises a dinucleophile reagent, such as a hydroxyla ine. Any timing group that is known in the photographic art is useful as the timing group between the PUG and the blocking group in the present invention. Examples of useful timing groups are described in, for example. U.S. Patents 4,248,962 and 4,409,323 and European Patent Application 255,085.

The particular timing groups employed, including the linkage by which they are attached to the PUG and the blocking group and the nature of the substituents on the timing group (e.g. , ballast groups) can be varied to help control such parameters as rate and time of bond cleavage of the

blocking group and the PUG as well as diffusibility of the PUG and substituent groups. The substituents on the timing group can be varied to control the diffusibility or mobility of the timing group itself as well as the PUG. A substituent on the timing group can constitute a ballast to prevent diffusion of the filter dye moiety until release from the timing group.

If the PUG is joined to the blocking group only through the (ballasted or unballasted) timing group, then the cleavage of the bond between the timing group and the blocking group releases the timing group and the PUG as a unit. The particular timing group in this case can control the rate and distance of diffusion in the photographic material before the PUG is released from the timing group. The timing group should not contain a structure that inhibits the reaction of the blocking group with a dinucleophile reagent. In the formula as described timing groups T, and T ₂ are independently selected to provide the desired rate and time of release of the PUG upon processing. The timing groups T, and T ₂ can be the same or different. Examples of preferred timing groups for T, and T ₂ are as follows:

— E,—O—CH _j —PUG

wherein E ₂ and PUG are as described; and R^, R^, and P,, are hydrogen or substituents, such as alkyl, nitro, chloro, sulfonamido, or ballasted substituents such as long chain alkyl (containing 5 to 40 carbon atoms) , long chain alkyl or alkaryl sulfonamido or amido, etc.

Other examples of useful timing groups are described in, for example, U.S. Patent 4,248,962 and U.S. 4,772,537. In the blocking group as described the two electrophilic groups, E, and E-^, can be any electrophilic group that enables nucleophilic displacement reaction to occur upon reaction of the blocking group with dinucleophile reagent. While carbonyl groups are highly preferred as the electrophilic groups, other .examples of useful electrophilic groups are as follows:

-C(R _f ) ₂ - wherein R, is a substituent that causes the attached carbon atom to be an electrophilic center.

Highly preferred groups in the blocking group described containing Z, Y ² and R ₃ are as follows:

wherein R _q is alkyl, such as methyl, ethyl, n-propyl, i-propyl, and butyl, or aryl, such as phenyl, benzyl or substituted phenyl or other substituents such as alkoxy, chloro and amido, as well as ballasted substituents such as long chain alkyl or alkaryl; and,

O o

wherein R ₄ is as described; R^ and R _4b are individually as described, such as methyl, ethyl, n- propyl, i-propyl, butyl, phenyl, benzyl, and substituted phenyl, or other substituents such as alkoxy, chloro and araido, which can also be ballasted.

In a preferred embodiment, the PUG is a filter dye. The blocked filter dyes as described can be used in photographic materials and in ways that filter dyes have been used in the photographic art.

Photographic elements according to the invention can be processed by conventional technigues in which color forming couplers and color developing agents are incorporated in separate processing solutions or compositions or in the photographic element. Optionally, blocked color developing agents can be incorporated in the photographic element and simplified processing solutions used for processing the element.

The photographic elements can be single color elements or multicolor elements- Multicolor elements contain dye image-forming units sensitive to each of the three primary regions of the visible spectrum. Each unit can be comprised of a single emulsion layer or of multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the photographic art- In an alternative format, the emulsions sensitive to each

of the three primary regions of the spectrum can be disposed as a single segmented layer, such as by the use of microvessels as described in U.S. Patent 4,362,806. A typical multicolor photographic element comprises a support bearing a cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta dye image-forming unit comprising at least one green- sensitive silver halide emulsion layer having associated therewith at least one magenta dye- forming coupler, and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element can contain added layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like. The blocked photographically useful compounds as described can be present in and/or associated with one or more of the layers of the photographic element. The compounds can be in an emulsion layer and/or in an adjacent layer. In the following discussion of materials useful in the emulsions and elements of the invention, reference will be made to Research Disclosure, December 1978, Item No. 17643, published by Industrial Opportunities Ltd., Homewell Havant, Hampshire, P09 1EF, U.K., the disclosures of which are incorporated herein by reference. The

SUBSTITUTESHEET

publication will be identified hereinafter by the term "Research Disclosure".

The silver halide emulsions employed in the elements can be comprised of silver bromide, silver chloride, silver iodide, silver chlorobromide, silver chloroiodide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The emulsions can include coarse, medium or fine silver halide grains. High aspect ratio tabular grain emulsions are specifically contemplated, such as those described by Mignot U.S. Patent 4,386,156, Wey U.S. Patent 4,399,215, Maskasky U.S. Patent 4,400,463, Wey et al. U.S. Patent 4,414,306, Daubendiek et al. U.S. Patent 4,414,310, Solberg et al. U.S. Patent 4,433,048, Wilgus U.S Patent 4,434,226, Maskasky U.S. Patent 4,435,501, Evans et al. U.S. Patent 4,504,570, Maskasky U.S. Patent 4,643,966, and Daubendiek et al. U.S. Patents 4,672,027 and 4,693,964. Also specifically contemplated are those silver bromoiodide grains with a higher molar proportion of iodide in the core of the grain than in the periphery of the grain, such as those described in US 4,379,837; US 4,444,877; US 4,565,778; US 4,636,461; US 4,665,012; US 4,668,614; US 4,686,178; US 4,728,602; GB 1,027,146; JA 54/48,521; and EP 264,954. The silver halide emulsions can be either monodisperse or polydisperse as precipitated. The grain size distribution of the emulsions can be controlled by silver halide grain separation technigues or by blending silver halide emulsions of differing grain

SUBSTITUTESHEET

sizes.

Sensitizing compounds, such as compounds of copper, thallium, lead, bismuth, cadmium and Group VIII noble metals, can be present during precipitation of the silver halide emulsion.

The emulsions can be surface-sensitive emulsions, that is, emulsions that form latent images primarily on the surfaces of the silver halide grains, or internal latent image-forming emulsions, that is, emulsions that form latent images predominantly in the interior of the silver halide grains. The emulsions can be negative- working emulsions, such as surface-sensitive emulsions or unfogged internal latent image-forming emulsions, or direct-positive emulsions of the unfogged, internal latent image-forming type, which are positive-working when development is conducted with uniform light exposure or in the -presence of a nucleating agent. The silver halide emulsions can be surface sensitized. Noble metal (e.g., gold), middle chalcogen (e.g., sulfur, selenium, or tellurium), and reduction sensitizers, employed individually or in combination, are specifically contemplated. Typical chemical sensitizers are listed in Research Disclosure, Item 17643, cited above, Section III.

The silver halide emulsions can be spectrally sensitized with dyes from a variety of classes, including the polymethine dye class, which includes the cyanines, merocyanines, complex cyanines and merocyanines (i.e., tri-, tetra-, and poly-nuclear

_S UB _S TI _T UTESHEET

cyanines and merocyanines) , oxonols, hemioxonols, styryls, merostyryls, and strepto-cyanines. Illustrative spectral sensitizing dyes are disclosed in Research Disclosure. Item 17643, cited above, Section IV.

Suitable vehicles for the emulsion layers and other layers of elements of this invention are described in Research Disclosure. Item 17643, Section IX and the publications cited therein. In addition to the couplers described herein the elements of this invention can include additional couplers as described in Research Disclosure Section VII, paragraphs D, E, F and G and the publications cited therein. These additional couplers can be incorporated as described in Research Disclosure Section VII, paragraph C and the publications cited therein.

The photographic elements of this invention can contain brighteners (Research Disclosure Section V) , antifoggants and stabilizers (Research Disclosure Section VI) , antistain agents and image dye stabilizers (Research Disclosure Section VII, paragraphs I and J) , light absorbing and scattering materials (Research Disclosure Section VIII) , hardeners (Research Disclosure Section X) , coating aids (Research Disclosure Section XI) , plasticizers and lubricants (Research Disclosure Section XII) , antistatic agents (Research Disclosure Section XIII) , matting agents (Research Disclosure Section XVI) and development modifiers (Research Disclosure Section XXI) .

S _U BSTITUTESHEET

The photographic elements can be coated on a variety of supports as described in Research Disclosure Section XVII and the references described therein. Photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image as described in Research Disclosure Section XVIII and then 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 in turn reacts with the coupler to yield a dye.

Preferred color developing agents are p- phenylene diamines. Especially preferred are 4- amino-3-methyl-N,N-diethylaniline hydrochloride, 4- amino-3-methyl-N-ethyl-N-/?-(methanesulfonamido) - ethylaniline sulfate hydrate, 4-amino-3-methyl-N- ethyl-N-3-hydroxyethylaniline sulfate, A-a ino-3-β-

(methanes lfonamido)ethyl-N,N-diethylaniline hydrochloride and 4-amino-N-ethyl-N-(2-methoxy- ethyl)-m-toluidine di-p-toluene sulfonic acid.

With negative-working silver halide, the processing step described above provides a negative image. The described elements are preferably processed in the known C-41 color process as described in, for example, the British Journal of Photography Annual of 1988, pages 196 - 198. To

SUBSTITUTESHEET

provide a positive (or reversal) image, the color development step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but* not form dye, and then uniformly fogging the element to render unexposed silver halide developable. Alternatively, a direct positive emulsion can be employed to obtain a positive image.

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

In processing it is necessary that the described dinucleophile reagent, such as a hydroxylamine, be present in the processing solution that is to be used to release or unblock the blocked photographically useful compound at the time desired. The concentration of the dinucleophile reagent in the processing solution can vary depending on such factors as the particular processing solution components, the particular dinucleophile reagent, the processing time and temperature, the particular photographic element to be processed, the desired image and the like. When the dinucleophile reagent is present in a color developer solution, the concentration of the dinucleophile reagent is typically within the range of 10 ^"5 moles to 1 mole per liter of solution.

The blocked photographically useful compounds according to the invention can be prepared by methods and steps known in the organic compound synthesis art.

SUBSTITUTESHEET

A typical method of preparing a blocked photographically useful compound is as follows: Synthesis I: Preparation of an intermediate

2.2-dimethyl-3-oxobutyryl chloride fGl)

O O

|| || Kc^cH^a

CH—C-CH.—C-OCH, .

Gl

UB _S TITUTESHEET

This illustrative intermediate compound Gl can be reacted with a photographically useful group (PUG) to provide a blocked photographically useful compound as described. A 2-liter, 3-necked round-bottomed flask containing ethyl acetoacetate (65 g, 0.5 mole), t- butanol (200 ml) , and tetrahydrofuran (200 ml) was fitted with thermometer, mechanical stirrer, nitrogen inlet, and addition funnel topped with an ice water condenser. The mixture was cooled to 0°C and stirred vigorously under a slow nitrogen stream while adding potassium t-butoxide (56 g, 0.5 mole) slowly (temp. <20°C) . A homogeneous solution resulted after about 5 minutes. Methyl iodide (32 ml, 0.5 mole) was added via the addition funnel while the temperature rose to about 10°C. The ice bath was replaced with a water bath at room temperature (20°C) before stirring the mixture for an additional 30 minutes while potassium iodide precipitated. The mixture was cooled again to 0°C before adding more methyl iodide (40 ml) and then potassium t-butoxide (56 g, 0.5 mole) (temp. <30°C) - The mixture was stirred at room temperature for 48 hours and then diluted with about 1 liter of water and 0.5 liter of saturated NaCl solution before the mixture was extracted with ether. The ether solution was washed with 0.1N NaOH and then with IN HC1, dried over magnesium sulfate, and concentrated to an oil. The crude dimethylated ethyl acetoacetate (64 g, 81% yield) had an nmr spectrum that was consistent with the expected compound.

The crude di ethylated ester (64 g, approx. 0.4 mole), NaOH (48 g, 1.2 mole), water (320 ml), and a trace of indicator dye (Metanil Yellow) were stirred for 18 hours until a homogeneous solution resulted. Residual alkali-insoluble material was removed by washing with a small amount of ether. The alkaline solution was then cooled in ice water and neutralized carefully with concentrated HCl (approx. 100 ml) until the indicator dye turned purple. Saturated NaCl was added to the cold solution before extracting several times with methylene chloride. The extracts were dried over sodium sulfate, filtered and concentrated at 30°C to yield the crude acid as an oil (50 g) (the acid solidifies at ice temperatures) . The nmr spectrum showed that a small amount of ethanol was present in the crude acid. In order to avoid excessive decarboxylation, the acid was used immediately by reacting with oxalyl chloride (75 ml, 0.86 mole) and a trace of triethylamine at room temperature for 24 hours. The mixture was concentrated at 30°C using a rotary evaporator with water aspirator vacuum. Excess oxalyl chloride was removed by codistillation with methylene chloride to yield crude 2,2-dimethyl- 3-oxobutyryl chloride (49 g, 82%) . A portion of the crude (45 g) was distilled through a six inch Vigreaux column under water aspirator vacuum (bp 50- 55°C) to yield purified colorless product (30 g, 67%) . A small amount of impurity containing an ethoxy group distilled with the later fractions of product. This impurity could be avoided by complete

removal of ethanol prior to acid chloride formation. Other illustrative intermediate compounds include G2 and G3 and are represented by the formulas:

Synthesis II: Preparation of an intermediate 2- methyl-3-oxocvclohexanoyl chloride (G2)

A 500-ml, 3-necked flask containing ethyl 2- cyclohexanonecarboxylate (17 g, 0.1 mole), t-butanol (75 ml) , and tetrahydrofuran (15 ml) was fitted with mechanical stirrer and addition funnel topped with an ice water condenser. The mixture was cooled to in an ice bath and stirred vigorously while adding potassium t-butoxide (11.2 g, 0.1 mole). A homogeneous solution resulted after about 5 minutes. The thick suspension was warmed to room temperature, treated with methyl iodide (14 ml, 0.2 mole) in 30 ml of THF, and then stirred for 3 hours. Water saturated with NaCl was added before extracting the alkylated ester into ether. The ether extract was

washed once with 0.IN NaOH to remove traces of unalkylated ester and then with agueous HC1 before drying over magnesium sulfate and concentrating to an oil (18.7 g) under reduced pressure. The crude methylated ester (18.6 g, approximately 0.1 mole), NaOH (12 g, 0.3 mole), water (80 ml) , and a trace of Metanil Yellow dye were stirred vigorously for 18 hours to obtain a homogeneous solution. (The nmr spectrum of the saponification product was definitive for simple saponification of the ester without cleavage of the cyclohexane ring.) The alkaline solution was cooled in ice water and acidified with concentrated HC1 (approximately 30 ml) until the indicator dye just turned purple. Methylene chloride was used to extract the carboxylic acid. After drying over sodium sulfate, the extracts were concentrated at room temperature under water aspirator vacuum. Residual ethanol was chased with methylene chloride leaving crude keto acid (14.9 g, 95%) as an oil.

The acid was mixed with oxalyl chloride (18 ml, 0.21 mole) and allowed to stand for 18 hours before being concentrated under aspirator vacuum at 30°C; residual oxalyl chloride was chased with methylene chloride. Crude 2-methyl-3- oxocyclohexanoyl chloride (16.4 g, approximately 100%) could be used in applications or distilled under aspirator vacuum, bp 90-100°C. The nmr spectrum consisted of broad absorption of the ring hydrogens between 1.5 and 3 ppm and a methyl group singlet at 1.45 ppm.

^T he ^f ol ^l owing is a specific illustrative synthesis o ^f _a ^b locked filter dye involving reaction with compound G _l :

SUBSTITUTE SHEET

(Gl) (B)

CO,H

SUBSTITUTE SHEET

Preparation of (A) :

3-Amino-4-hydroxybenzyl alcohol (34.8 g, 0.25 mole, prepared as in U.S. Patent No. 4,840,884, incorporated by reference) was completely dissolved in pyridine (200 ml) in a 500 ml flask fitted with addition funnel, thermometer and mechanical stirrer. After cooling in ice, the mixture was treated with a solution of hexadecane sulfonyl chloride (81.2 g, 0.25 mole in 250 ml THF) dropwise over about 30 minutes. The mixture was allowed to warm to room temperature over 1 hour, and then diluted with one liter of water. The precipitated product was filtered, washed with water and dried to yield 95 g (89%) of (A) . Preparation of (B) :

The sulfonamide (A) (42.7 g, 0.1 mole) was dissolved in a mixture of pyridine (100 ml) , THF (600 ml) and triethylamine (28 ml, 0.2 mole) and then cooled in an ice bath. Acid chloride blocking reagent (Gl) (14.9 g, 0.1 mole in 100 ml dichloromethane) was added dropwise over about 15 minutes. The mixture was allowed to warm to room temperature over about 1 hour, then diluted with a mixture of 900 ml dichloromethane, washed with aqueous HCl (150 ml cone. HC1 in 1.5 1 water) and then with water. The organic layer was dried with MgS0 ₄ and concentrated to a solid. The solid was then extracted with dichloromethane (250 ml) , and the extract was concentrated to a syrup which

crystallized from heptane to yield 38-5 g (71%) of

(B).

Preparation of fC) :

Phosgene (150 ml of 1.6 M solution in toluene, 0.24 mole) was added to a solution of benzylic alcohol (B) in 150 ml of dichloromethane. The mixture was stirred for 4 hours at room temperature before concentrating at 35°C under a water aspirator vacuum. Residual toluene was removed under oil pump vacuum. The residue crystallized as a waxy solid (C) (34.7 g) . Preparation of (D) :

3-Amino-N,N-dimethylaniline dihydrochloride (7.3 g, 0.035 mole) was stirred vigorously with NaHCO _j (90 ml, IN) and dichloromethane (75 ml) in an ice bath. Chloroformate (C) (10.8 g, 0.018 mole) was added and the mixture was stirred for 30 minutes. The organic phase was separated, washed with a little dilute HCl, dried over MgS0 _< , and concentrated to a syrupy product (D) (13 g) . Preparation of fE) :

Coupler (D) (2.5 g, 3.6 mmole) was dissolved in a mixture of THF (20 ml), acetic acid (10 ml), pyridine (5 ml) and water (5 ml) and then cooled in an ice bath. Diazonium solution was prepared by dissolving 3-aminobenzoic acid (493 mg, 3.6 mmole) in HCl (15 ml, 2N) at 0°C, adding NaN0 ₂ (248 mg, 3.6 mmole) , and stirring for 5 minutes. This solution was added to the solution of coupler (D) and stirred for about 30 minutes, then warmed to room temperature. The precipitate was collected,

dissolved in dichloromethane, washed with water, dried, and concentrated to a syrup which crystallized from methanol to yield filter dye (E) (2.0 g).

The following is a specific illustrative synthesis of a blocked filter dye involving reaction with compound G2:

Synthesis IV: Preparation of Compound (20)

Σ.CO,

OH

CH. CH.

(F) (G)

)

STITUTE SHEET

N— N

SUBSTITUTE SHEET

Preparation of (F) :

A mixture of methyl 2-bromotetradecanoate (24 g, 0.075 mole), t-butyl 2-hydroxybenzoate (14.5 g, 0.075 mole), K ₂ C0 ₃ (30 g, 0.22 mole), KI (1.2 g, 7.5 mmole) , and acetone (300 ml) was refluxed for 24 hours. Ethyl acetate (300 ml) was added, and the mixture was washed 3 times with water (150 ml portions) , dried and concentrated to a syrupy product (F) (30 g) . Preparation of (G) :

The methyl ester (F) (50 g, 0.115 mole) was dissolved in THF (200 ml) and methanol (100 ml) and treated with NaOH (11.5 g, 0.29 mole in 30 ml of water) . After stirring for about 30 minutes, the mixture was diluted with 250 ml of ethyl acetate, washed with 150 ml of 2N HCl and then with water, dried and concentrated to a syrup product acid (G) (49 g). Preparation of fH : Acid (G) (100.8 g, 0.24 mole), ethyldiisopropylamine (42 ml, 0.24 mole) and THF (250 ml) were mixed and cooled in ice. A solution of isobutyl chloroformate (31.2 ml, 0.24 mole) in 50 ml of THF was added slowly with stirring over about 5 minutes to the cold solution of (G) and allowed to react for 40 minutes. This solution of mixed anhydride was transferred to an addition funnel and added over about 5 minutes to an ice cold mixture of 3-amino-4-hydroxybenzyl alcohol (41.6 g, 0.3 mole) in pyridine (200 ml) and then allowed to warm to room temperature. Subseguently the mixture was

ESHEET

diluted with ethyl acetate, washed with excess IN HCl and then water, dried, concentrated to 130 g of crude product, and chromatographed on silica gel using dichloromethane/heptane/ethyl acetate (5/3/2) as eluent. Amide (H) was obtained as a syrup (70

9 ⁾ -

Preparation of (I) :

Amido alcohol (H) (53.7 g, 0.1 mole), acid chloride (G2) (22.5 g, 0.1 mole) and THF (200 ml) were combined and cooled in ice. Triethylamine (28 ml, 0.2 mole) was added dropwise over about 20 minutes with vigorous stirring. The mixture was allowed to come to room temperature, then diluted with ethyl acetate, washed with excess IN HCl and then water, dried, concentrated and chromatographed using the same eluent as for (H) . Ester alcohol (I) was obtained (35 g) . Preparation of (J) :

Glutaryl dichloride (1.2 ml, 9 mmole), THF (20 ml) , and alcohol (I) (2 g, 3 mmole) were placed in a 100 ml flask, cooled in ice, and treated dropwise with triethylamine (0.9 ml, 6 mmole). After 30 minutes, the mixture was diluted with ethyl acetate, washed with agueous HCl, dried and concentrated to a syrup. This syrup was stirred with a mixture of dimethylformamide (3 drops) , THF (20 ml) and oxalyl chloride (0.7 ml, 7.5 mmole) at room temperature for 1.5 hours. The mixture was then concentrated at 35°C under aspirator vacuum and chased 3 times with 50 ml portions of THF to afford crude acid chloride (J) (2.2 g) -

Preparation of fK) : l-(4-Aminophenyl)-3-methyl-2-pyrazolin-5-one (1.9 g, 10 mmole) and 2,6-lutidine (1.6 g, 15 mmole) were dissolved in 10 ml of dimethylformamide and cooled in an ice bath. Acid chloride (J) (8.1 g, 10 mmole) in 25 ml of THF (200 ml) were added slowly to the cold solution, stirred for about 30 minutes, and then diluted with ethyl acetate. The mixture was washed with agueous dilute HCl and then with water, dried, and concentrated to crude pyrazolone coupler (K) (8.6 g). Preparation of fL) : p-Anisidine (260 mg, 2.1 mmole) in 15 ml of

2N HCl was cooled in ice and stirred vigorously while adding NaNO, (150 rag, 2.1 mmole). After stirring 5 minutes, the diazonium solution was added to a solution of coupler (K) (2 g, 2.1 mmole) in 25 ml of THF and 10 ml of pyridine at ice temperature with vigorous stirring. Dye formation was complete after 30 minutes. The mixture was diluted with ethyl acetate, washed with dilute HCl and then water, dried, concentrated, and chromatographed on silica gel (2:1:1 dichloromethane:heptane: ethyl acetate eluent) to yield filter dye (L) (2.0 g) . Preparation of (M) :

Filter dye (L) (2 g, 1.8 mmole) was dissolved in 15 ml of dichloromethane and 5 ml of trifluoroacetic acid and allowed to stand at room temperature for about 15 minutes until ester cleavage was complete as shown by TLC (same eluent as above) . The mixture was washed seguentially with

T _I TUTESHEET

excess IN NaCO, , water, IN HCl, and water, and then dried over MgSO, and concentrated to solid filter dye (M) (1-3 g) . The nmr spectrum in deuterodimethylsulfoxide confirmed the structural integrity of the ballasted filter dye.

The following blocked filter dyes are exemplary of compounds that can be prepared by the methods described. These blocked compounds can be incorporated and processed in a photographic element as described in Example l.

1 )

N= N

CO.H

2)

n-

C0 ₇ H

3)

N-N

C0 ₂ H

SUBSTITUTE SHEET

4)

n-

H-SQOL

SUBSTITUTE SHEET

7)

8)

9)

SUBSTITUTE SHEET

10)

ii)

SUBSTITUTE SHEET

12)

13)

CH

NCCRO^

15)

CH

N(CH ₃ ) ₂

16)

17)

N=N ή

C0,H

20)

OCH.

21)

NCCH .

22)

23)

OCH.

24)

25)

N(CH _ι α ,

26)

N=N

OCH,

27)

N-N

C0 ₂ H

28)

29)

C^-n

SUBSTITU

Example 1

Photographic elements were prepared by coating the following layers on a cellulose acetate film support (amounts of each compound are in rag/nr) : Emulsion Layer : gelatin (3767) green-sensitized silver bromoiodide (as Ag)

(1076) magenta image coupler (dispersed in tritolyl phosphate) (619) filter dye compound of the invention dispersed in diethyldodecanamide and coated at 0.215 millimoles/m ² .

A comparison coating containing 43-04 mg/irr of Carey Lea Silver (CLS, also called yellow colloidal silver) was prepared. This level of Carey Lea Silver gave approximately the same amount of blue light absorption as the filter dyes of the Example. Protective Overcoat :

Gelatin (2691) bisvinylsulfonylmethyl ether at 1.75% total gelatin.

The structure of the magenta image coupler is as follows:

Each photographic element was i agewise exposed to light through a graduated density test object in a commercial sensitometer to provide a developable latent image (3000°K light source, 0-4 step wedge, with ratten(TM) 12 plus 0.1ND filter). The resulting photographic films were processed using the following color developer solutions, then stopped, bleached, fixed, washed, and dried to produce stepped colored images.

Color Developing Solution:

800.0 raL water

34.20 g potassium carbonate, anhydrous

2.32 g potassium bicarbonate

0.38 g sodium sulfite, anhydrous 2.78 g sodium metabisulfite

1.20 mg potassium iodide

1-31 g sodium bromide

8.43 g diethylenetriaminepentaacetic acid pentasodium salt (40% solution) 2.41 g hydroxylamine sulfate (HAS)

4.52 g KODAK Color Developing Agent CD-4 and enough water to make 1.0 L total volume (pH =

10.0) .

For comparison purposes, the following color developer lacking HAS was prepared.

Color Developer without HAS:

900.0 L water

30.00 g potassium carbonate, anhydrous

2.0 g potassium sulfite

0.6 mg potassium iodide

1.25 g potassium bromide

3.55 g KODAK Color Developing Agent CD-4 and enough water to make 1.0 L total volume (pH =

10.0) .

The density of the film to blue and green light in areas of low exposure can be seen in Table I.

where Db and Dg refer to the densities to blue and green light in areas of minimum exposure after processing using the Color Developer Solution, and Db without HAS refers to the density to blue light in areas of minimum exposure after processing using Color Developer without HAS.

The data in Table I demonstrate that the inventive blocked filter dyes do not generate the unwanted increase in green density in areas of minimum exposure that is observed on incorporation of Carey Lea Silver. The low densities to blue light after processing demonstrate the desired complete removal of the dyes as a function of processing. The amount of blue light filtration afforded by the dyes can be seen in the high blue densities after a process without HAS. In the absence of this dinucleophile, the blue light absorption of the filter dyes is retained after processing.

Example 2

To facilitate demonstration of the advantages of the filter dyes with respect to light absorption during exposure, coatings lacking the silver halide and the magenta image coupler were prepared. The unsensitized coatings were evaluated for the hue of the dye and for the loss of density during processing. The comparative absorption spectra for some yellow filter dyes and Carey Lea Silver are shown in Fig. 1. Carey Lea Silver is found to have a significant amount of unwanted absorption in the

SUBSTITUTESHEET

-60-

green light region of the visible spectrum (about 550 nm) ; the inventive blocked ilter dyes are found to be sharper cutting on the long wavelength end of the absorption spectra and have little green light absorption.

The spectral properties for some of the filter dyes are summarized in Table II.

where lambda-max is the wavelength of maximum absorption, Dmax is the density at lambda-max, Db is the blue density before processing, and Da is the blue density after processing.

The data in Table II demonstrate the control of hue and absorptivity available from these compounds while still retaining adeguate removal during processing. It is to be understood that the foregoing detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.