[0001] This invention relates to a new photographic naphtholic coupler capable upon oxidative
coupling of forming a dye that is capable of being washed out of the photographic
material containing the coupler upon processing and to photographic materials and
processes comprising the naphtholic coupler.
[0002] Various couplers are known in photographic materials and processes. One of the classes
of photographic couplers includes naphtholic couplers that 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.
Such naphtholic couplers are also known which are capable of forming dyes upon oxidative
coupling that can be washed out of the photographic material upon processing. These
naphtholic couplers are described in, for example, U.S. Patent 4,482,629.
[0003] The naphtholic couplers that are capable of forming dyes that can be washed out of
the photographic material upon photographic processing contain a water solubilizing
group, such as a carboxy group or sulfonic acid group, substituted on a group in the
2- position of the naphtholic coupler. It has been desirable to provide a naphtholic
coupler that is not as expensive to manufacture as the described naphtholic couplers
and still provides a useful dye that can be washed out of the photographic material
with the added advantage that the coupler enables a lower concentration of coupler
to be used in a photographic element without significantly changing imaging results.
[0004] It has also been desirable to provide such a naphtholic coupler that contains a coupling-off
group that enables desired acutance and desired interimage effects in a color photographic
silver halide material and process at lower concentrations of coupler.
[0005] The present invention solves these problems by providing a photographic material
comprising a support bearing at least one photographic silver halide emulsion layer
and having in or adjacent the emulsion layer an immobile naphtholic coupler capable
upon oxidative coupling of forming a dye that is capable of being washed out of the
photographic element upon photographic processing, wherein the immobile naphtholic
coupler comprises a ballast free naphtholic coupler moiety comprising 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).
[0006] The immobile naphtholic coupler is typically represented by the formula:

wherein Z is a ballasted coupling-off group, R₁ is a ballast-free substituent that
does not adversely affect the desired properties of the coupler and dye, and z is
0, 1, 2 or 3. R₁ does not comprise a ballast group because such a group adversely
affects wash-out properties of the dye formed from the naphtholic coupler.
[0007] The ballasted coupling-off group (Z) enables 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 that 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 in the location in which it was coated.
The coupling-off group preferably comprises a releasable photographically useful group
(PUG) which is released upon photographic processing. The PUG either is immobilized
to remain in the location of the element in which it was coated or the PUG is mobile
to allow it, after release, to move to a location in the element at which it can serve
its intended function.
[0008] A preferred naphtholic coupler as described comprises a coupling-off group represented
by the formula:
-(LINK)
n-(TIME)
m-PUG
wherein
TIME is a releasable timing group capable of being released from the LINK moiety
during photographic processing;
LINK is a releasable linking group capable of being released from the naphtholic
coupler moiety upon oxidative coupling of the naphtholic coupler;
n and m individually are 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.
[0009] A process of forming an image having the described advantages comprises developing
an exposed photographic element as described by means of a color developing agent
in the presence of the described naphtholic coupler and washing-out the dye formed
from the naphtholic coupler.
[0010] Any naphtholic coupler moiety is useful that can contain the -CONH₂ group in the
2- position and a coupling-off group in the 4- position and can form a compound, especially
a dye, that can be washed out of the element upon oxidative coupling of the coupler.
It will be appreciated that depending upon the particular developing agent and the
particular type of processing, the reaction product of the coupler moiety and the
oxidized developing agent can be colored or colorless. Examples of useful naphtholic
coupler moieties can be unsubstituted except for the required substituents in the
2- and 4- positions as described. Optionally the naphtholic coupler moieties in addition
to the substituents in the 2- and 4- positions can contain other substituents that
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 naphtholic
coupler moieties include those described in, for example, the following patents in
which the group described in the 2- position is replaced with -CONH₂, especially those
having a ballasted coupling-off group: U.S. Patents 4,840,884; 4,861,701; 2,474,293;
3,227,554; 4,482,629 and 4,857,447.
[0011] Any coupling-off group containing a ballast group known in the photographic art is
useful in the 4- position of the described naphtholic coupler moiety. Examples of
useful coupling-off groups are described in, for example, U.S. Patent 4,861,701. Preferred
coupling-off groups are those that enable release of a PUG upon photographic processing,
especially those that have a releasable timing group between the bond to the coupling
position of the coupler and the releasable PUG. Preferred timing groups are described
in, for example, U.S. Patents 4,861,701; 4,248,962; 4,409,323; 4,482,629 and 4,857,447.
[0012] A preferred naphtholic coupler is represented by formula:

wherein
X represents the atoms completing a 5-, 6- or 7-member ring, such as an aryl or
heterocyclic group;
R₁ is a ballast-free substituent;
z is 0, 1, 2 or 3;
BALL is a ballast group known in the photographic art;
T² is a releasable timing group;
R₂ and R₃ individually are hydrogen,
unsubstituted or substituted alkyl or aryl, such as alkyl containing 1 to 40 carbon
atoms or aryl containing 6 to 40 carbon atoms, such as a phenyl or naphthyl group;
and,
q is 0, 1 or 2.
[0013] T² is, for example, a group that enables release of PUG by means of intramolecular
nucleophilic displacement, such as described in U.S. 4,248,962 and U.S. 4,861,701.
[0014] In the case of such couplers that release a PUG by means of a timing group, 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 and the remainder of the
coupling-off group is cleaved. Bond cleavage between the PUG and the remainder of
the coupling-off group preferably does not involve the action of oxidized color developing
agent. The cleavage of the bond between the PUG and the remainder of the coupling-off
group can involve any reaction known in the photographic art for cleavage of such
groups, for example an intramolecular nucleophilic displacement reaction or other
elimination reaction.
[0015] Any ballast group known in the photographic art can be useful on the coupling-off
group. The ballast group (BALL) herein means an organic group of such size and configuration
as to confer on the coupler molecule sufficient bulk to render the coupler substantially
non-diffusible from 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 containing, for example, 8 to 40 carbon atoms. Other useful ballast
groups include sulfonamido groups containing 8 to 40 carbon atoms, carbonamido, carbamoyl,
sulfamoyl, ester, sulfone, ether, thioether and amino groups.
[0016] A typical timing group T² is a group that enables release of a PUG by means of intramolecular
nucleophilic displacement, such as described in U.S. Patents 4,861,701; 4,857,440;
4,847,185 and 4,248,962.
[0017] Illustrative timing groups T² are as follows:

and other illustrative groups described in U.S. Patent 4,857,447.
[0018] In the above structures, R₄, R₅, R₆, R
6a, R₇, R₈, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇, R₁₈, R₁₉, R₂₀, R₂₁, R₂₂, R₂₃
and R₂₄ individually are hydrogen or substituents that 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.
[0019] As used herein the term "naphtholic coupler" refers to the entire compound including
the coupler moiety and the coupling-off group. The term "naphtholic coupler moiety"
herein refers to that portion of the coupler other than the coupling-off group.
[0020] The PUG can be any group that is typically made available in a photographic element
in an imagewise fashion. The PUG can be a photographic reagent or a photographic dye.
A photographic reagent herein is a moiety that upon release 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 competing coupler,
a dye-forming coupler, or a development inhibitor releasing coupler (DIR coupler)),
a dye precursor, a dye, a developing agent (for example, a competing developing agent,
a dye-forming developing agent, or a silver halide developing agent), a silver complexing
agent, a fixing agent, an image toner, a stabilizer, a hardener, a tanning agent,
a fogging agent, an ultraviolet radiation absorber, an antifoggant, a nucleator, a
chemical or spectral sensitizer or a desensitizer.
[0021] The PUG can be present in the coupling-off group as a preformed species or it can
be present in a blocked form or as a precursor. The PUG can be for example a preformed
development inhibitor or the development inhibiting function can be blocked by being
the point of attachment to the carbonyl group bonded to PUG in the coupling-off group.
Other examples are a preformed dye, a dye that is blocked to shift its absorption,
and a leuco dye.
[0022] A preferred naphtholic coupler as described is a photographic coupler containing
a naphtholic coupler moiety and a PUG containing a hetero atom from VIb or Vb of the
Periodic Table having a negative valence of 2 or 3 bonded to a carbonyl group of the
coupling-off group.
[0023] Any couplers known to be useful in the photographic art can be used with the described
naphtholic couplers and in various locations known in the art in a photographic element.
There follows a listing of patents and publications that describe representative couplers
that can be useful in combination with the described naphtholic couplers:
I. COUP's
[0024]
A. Couplers which form cyan dyes upon reaction with oxidized color developing agents
are described in such representative patents and publications as: U.S. Pat. Nos. 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 "Farbkuppler-eine Literaturübersicht," published in Agfa Mitteilungen, Band III,
pp. 156-175 (1961).
Preferably such couplers are phenols and naphthols that form cyan dyes on reaction
with oxidized color developing agents.
B. Couplers which form magenta dyes upon reaction with oxidized color developing agent
are described in such representative patents and publications as: U.S. Pat. Nos. 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 "Farbkuppler-eine
Literaturübersicht," published in Agfa Mitteilungen,Band III, pp. 126-156 (1961).
Preferably such couplers are pyrazolones and pyrazolotriazoles that form magenta dyes
upon reaction with oxidized color developing agents.
C. Couplers which form yellow dyes upon reaction with oxidized and color developing
agent are described in such representative patents and publications as: U.S. Pat.
Nos. 2,875,057; 2,407,210; 3,265,506; 2,298,443; 3,048,194; 3,447,928 and "Farbkuppler-eine
Literaturübersicht," published in Agfa Mitteilungen, Band III, pp. 112-126 (1961).
Preferably such couplers are acylacetamides, such as benzoylacetanilides and pivaloylacetanilides
that 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.K. Patent No. 861,138; U.S.
Pat. 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 on reaction
with oxidized color developing agent.
[0025] Any releasable PUG known in the photographic art is useful in the coupling-off group
as described. Examples of useful PUG's are as follows:
PUG's
[0026]
A. PUG's which form development inhibitors upon release are described in such representative
patents as U.S. Pat. Nos. 3,227,554; 3,384,657; 3,615,506; 3,617,291; 3,733,201; 4,861,701
and U.K. Pat. 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:

where R₂₉ is unsubstituted or substituted alkyl, such as butyl, 1-ethylpentyl, and
2-ethoxyethyl, or alkylthio, such as butylthio and octylthio; R₂₅ and R₂₆ individually
are hydrogen, alkyl of 1 to 8 carbon atoms such as methyl, ethyl, or butyl, phenyl
or substituted phenyl; and R₂₇ and R₂₈ individually are hydrogen or one or more halogen
such as chloro, fluoro or bromo; alkyl of 1 to 4 carbon atoms, carboxyl, esters, such
as -COOCH₃, or other substituents such as -NHCOOCH₃, -SO₂OCH₃, -OCH₂CH₂SO₂CH₃,

or nitro groups.
B. PUG's which are, or form, dyes 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 can be metal complexed or metal complexable. Representative
patents describing such dyes are U.S. Pat. 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's which are couplers:
Couplers released can be nondiffusible color-forming couplers, non-color forming
couplers or diffusible competing couplers. Representative patents and publications
describing competing couplers are: "On the Chemistry of White Couplers," by W. Püschel,
Agfa-Gevaert AG Mitteilungen and der Forschungs-Laboratorium der Agfa-Gevaert AG,
Springer Verlag, 1954, pp. 352-367; U.S. Pat. Nos. 2,998,314; 2,808,329; 2,689,793;
2,742,832; German Pat. No. 1,168,769 and British Pat. No. 907,274. Structures of preferred
competing couplers are:

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

where R₃₅, which is the same as R₃₄ as defined above, and R₃₆ is halogen, aryloxy,
arylthio, or a development inhibitor, such as a mercaptotetrazole, such as phenylmercaptotetrazole
or ethylmercaptotetrazole.
D. PUG's which form developing agents:
Developing agents released can be color developing agents, black-and-white developing
agents or cross-oxidizing developing agents. They include aminophenols, phenylene
diamines, hydroquinones and pyrazolidones. Representative patents are: U.S. Pat. Nos.
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 developing agents are:

where R₃₇ is hydrogen or alkyl of 1 to 4 carbon atoms and R₃₈ is hydrogen or one
or more halogen such as chloro or bromo; or alkyl of 1 to 4 carbon atoms such as methyl,
ethyl or butyl groups.

where R₃₈ is as defined above.

where R₃₉ is hydrogen or alkyl of 1 to 4 carbon atoms and R₄₀, R₄₁, R₄₂, R₄₃ and
R₄₄ are individually hydrogen, alkyl of 1 to 4 carbon atoms such as methyl or ethyl;
hydroxyalkyl of 1 to 4 carbon atoms such as hydroxymethyl or hydroxyethyl or sulfoalkyl
containing 1 to 4 carbon atoms.
E. PUG's which are bleach inhibitors:
Representative patents are U.S. Pat. Nos. 3,705,801; 3,715,208; and German OLS
No. 2,405,279. Structures of preferred bleach inhibitors are:

where R₄₅ is an alkyl group of 6 to 20 carbon atoms.
F. PUG's which are bleach accelerators:

wherein R₄₆ is hydrogen, alkyl, such as ethyl and butyl, alkoxy, such as ethoxy and
butoxy, or alkylthio, such as ethylthio and butylthio, for example containing 1 to
6 carbon atoms, and which may be unsubstituted or substituted; R₄₇ is hydrogen, alkyl
or aryl, such as phenyl; R₄₈ and R₄₉ are individually alkyl, such as alkyl containing
1 to 6 carbon atoms, for example ethyl and butyl; z is 1 to 6.
[0027] The image dye-forming couplers can be incorporated in photographic elements and/or
in photographic processing solutions, such as developer solutions, so that upon development
of an exposed photographic element they will be in reactive association with oxidized
color developing agent. Coupler compounds incorporated in photographic processing
solutions should be of such molecular size and configuration that they will diffuse
through photographic layers with the processing solution. When incorporated in a photographic
element, as a general rule, the coupler compounds should be nondiffusible, that is
they should be of such molecular size and configuration that they will not significantly
diffuse or wander from the layer in which they are coated.
[0028] Photographic elements of this invention can be processed by conventional techniques
in which color forming couplers and color developing agents are incorporated in separate
processing solutions or compositions or in the element.
[0029] Photographic elements in which the compounds of this invention are incorporated can
be a simple element 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 in at least one of the silver halide emulsion layers and/or in at
least one other layer, such as an adjacent layer, where they will come into reactive
association with oxidized color developing agent which has developed silver halide
in the emulsion layer. The silver halide emulsion layer can contain or have associated
with it, other photographic coupler compounds, such as dye-forming couplers, colored
masking couplers, and/or competing couplers. These other photographic couplers can
form dyes of the same or different color and hue as the photographic couplers of this
invention. Additionally, the silver halide emulsion layers and other layers of the
photographic element can contain addenda conventionally contained in such layers.
[0030] A typical multilayer, multicolor photographic element can comprise a support having
thereon a red-sensitive silver halide emulsion unit having associated therewith a
cyan dye image-providing material, a green-sensitive silver halide emulsion unit having
associated therewith a magenta dye image-providing material and a blue-sensitive silver
halide emulsion unit having associated therewith a yellow dye image-providing material,
at least one of the silver halide emulsion units having associated therewith a photographic
coupler of the invention. Each silver halide emulsion unit can be composed of one
or more layers and the various units and layers can be arranged in different locations
with respect to one another.
[0031] The couplers of this invention can be incorporated in or associated with one or more
layers or units of the photographic element. For example, a layer or unit affected
by PUG can be controlled by incorporating in appropriate locations in the element
a scavenger layer which will confine the action of PUG to the desired layer or unit.
At least one of the layers of the photographic element can be, for example, a mordant
layer or a barrier layer.
[0032] The light sensitive silver halide emulsions can include coarse, regular or fine grain
silver halide crystals or mixtures thereof and can be comprised of such silver halides
as silver chloride, silver bromide, silver bromoiodide, silver chlorobromide, silver
chloroiodide, silver chlorobromoiodide and mixtures thereof. The emulsions can be
negative-working or direct-positive emulsions. They can form latent images predominantly
on the surface of the silver halide grains or predominantly on the interior of the
silver halide grains. They can be chemically and spectrally sensitized. The emulsions
typically will be gelatin emulsions although other hydrophilic colloids are useful.
Tabular grain light sensitive silver halides are particularly useful such as described
in
Research Disclosure, January 1983, Item No. 22534 and U.S. Patent 4,434,226.
[0033] The support can be any support used with photographic elements. Typical supports
include cellulose nitrate film, cellulose acetate film, polyvinylacetal film, polyethylene
terephthalate film, polycarbonate film and related films or resinous materials as
well as glass, paper, metal and the like. Typically, a flexible support is employed,
such as a polymeric film or paper support. Paper supports can be acetylated or coated
with baryta and/or an α₋olefin polymer, particularly a polymer of an α-olefin containing
2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymers
and the like.
[0034] It is preferred that the coupling-off group contain a releasable PUG. Depending upon
the nature of the particular PUG, the couplers can be incorporated in a photographic
element for different purposes and in different locations.
[0035] In the following discussion of suitable materials for use in the emulsions and elements
of this invention, reference will be made to
Research Disclosure. December 1978, Item 17643, published by Industrial Opportunities Ltd., Homewell Havant,
Hampshire, PO9 1EF, U.K. This publication will be identified hereafter by the term
"Research Disclosure".
[0036] The photographic elements can be coated on a variety of supports as described in
Research Disclosure Section XVII and the references described therein.
[0037] 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.
[0038] Preferred color developing agents useful in the invention are p-phenylene diamines.
Especially 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.
[0039] With negative working silver halide the processing step described above gives 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 not
form a 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.
[0040] Development is followed by the conventional steps of bleaching, fixing, or bleach-fixing,
to remove silver and silver halide, washing and drying.
[0041] Naphtholic couplers as described can be prepared by reactions and methods known in
the organic compound synthesis art. Similar reactions and methods are described in
U.S. Patent 4,482,629. Typically, the naphtholic coupler is prepared by the following
method:

Ph herein means phenyl.
Synthesis Example A: -
Compound (A2):
[0042] Phenyl-1,4-dihydroxy-2-naphthoate (100.0 g, 356.78 mmol) was dissolved in deoxygenated
tetrahydrofuran (500 mL) and deoxygenated methanol (500 mL) added. To this solution,
stirred at room temperature under the nitrogen atmosphere, was added ammonium acetate
(50.0 g, 648.63 mmol) followed by concentrated ammonium hydroxide (1.0 L). After stirring
for 3 hours the reaction was then poured into ice cold 2N-HCl (4.0 L) and enough concentrated
HCl added to bring the pH to 1. The resulting product, compound (A2) was filtered
off, washed well with water and air dried. The crude product was washed with dichloromethane
and air dried. Yield 62.0 g (72%).
Compound (A3):
[0043] Compound (A2) (50.0 g, 0.246 mol) was dissolved in dry pyridine (150 mL) and acetonitrile
(75 mL) added. The solution was stirred and cooled to -5 to 0°C. Ethyl chloroformate
(50 mL, 0.523 mol) was then added dropwise with stirring while maintaining the temperature
at 0°C. After the addition, the cooling bath was removed and the temperature allowed
to reach room temperature. The reaction mixture was then gradually heated to reflux
and the solvent allowed to distill off. This procedure was continued until the temperature
had risen to approximately 120°C and 150 mL of solvent had been collected. Heating
under reflux was continued for an additional 1 hour period. The reaction mixture was
then cooled to approximately 50°C and poured into 2N-HCl, (3.0 L) held at room temperature.
This suspension was then stirred for approximately 15 minutes, filtered and the residue
washed well with water, acetonitrile and finally ether. This gave the product, compound
(A3) sufficiently pure for the next step. Yield 43.5 g (77%).
Compound (A4):
[0044] Compound (A3) (23.0 g, 100.35 mmol) was taken up in deoxygenated dimethylsulphoxide
(250 mL) and deoxygenated water (25 mL) added. To this solution, stirred at room temperature
under nitrogen, was added 85%-potassium hydroxide (9.9 g, 150.53 mmol) and stirring
continued until dissolution, approximately 15 minutes. 4-Chloro-3-nitrobenzaldehyde
(18.62 mmol) was then added all at once and the resulting solution stirred at 60°C
for 1 hour. The reaction mixture was then poured into ice cold 2N-HCl (2.0 L) and
filtered off. The product, compound (A4), was washed with water and, while still wet,
slurried in methanol, filtered and washed with ether. This product was pure enough
to be used in the next step. Yield 28.0 g (74%).
Compound (A5):
[0045] Compound (A4) (28.0 g, 74.01 mmol), in a powdered 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. More tetrahydrofuran (50 mL) was added to aid
stirring. At the end of the sodium borohydride addition complete dissolution had been
achieved. The reaction was allowed to proceed for a further 15 minutes, then poured
into ice cold 2N-HCl (2.0 L) and the product filtered off. The product compound (A5)
was washed with methanol and while still wet with solvent, suspended in ethanol and
heated to reflux. The solution was cooled, filtered, washed with methanol, ether and
finally air dried. A second crop of material was obtained on concentrating the mother
liquor. Total yield 19.5 g (67%).
Compound (A6):
[0046] 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) and then
heated to 80°C for 1 hour. The resulting dark yellow-brown solution was cooled and
poured into ice cold 2N-HCl (2.0 L). The yellow product was filtered off, washed well
with water and air dried. Yield 17.7 g (100%).
Compound (A7):
[0047] Compound (A6) (17.7 g, 70 mmol) was dissolved in tetrahydrofuran (80 mL) and methanol
(300 mL) added. Raney-Nickel which had been washed several times with water and then
methanol was added and the solution hydrogenated at 55psi for 2 hours after which
hydrogen up-take had ceased. The catalyst was filtered off, washed with methanol and
the filtrate concentrated under reduced pressure to give the product, compound (A7).
This product was deemed sufficiently pure to be carried on to the next step. Yield
100%.
Compound (A8):
[0048] Compound (A7) (50.0 mmol) was dissolved in dry pyridine (150 mL) and hexadecylsulfonyl
chloride (16.2 g, 50.0 mmol) added. The solution was stirred at room temperature under
a nitrogen atmosphere for 30 minutes. The pyridine was concentrated under reduced
pressure and the residue 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 under reduced pressure and the residual oil crystallized from acetonitrile.
After filtering, washing with acetonitrile and drying, the yield of product compound
(A8) amounted to 16.3 g (53% calculated from compound (A5)).
Compound (A9):
[0049] Compound (A8) (16.3 g, 26.6 mmol) was dissolved in tetrahydrofuran (150 mL) to which
was added pyridine (3.2 mL, 39.90 mmol) followed by chloroacetic anhydride (6.82 g,
39.89 mmol) in tetrahydrofuran (30 mL) at a reasonably rapid rate. After stirring
at room temperature for 30 minutes the solvent was removed under reduced pressure
and the residue 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%).
Compound (A10):
[0050] Compound (A9) (12.2 g, 17.7 mmol) was dissolved in dimethylformamide (150 mL) To
which was added potassium iodide (4.4 g, 25.55 mmol) and aniline (8.2 mL, 88.5 mmol)
and the reaction mixture heated to 60°C for 1.5 hours. The reaction was poured into
2N-HCl and extracted with ethyl acetate (X2). The combined ethyl acetate extracts
were washed with 2N-HCl (X3), dried (MgSO₄), filtered and then concentrated. This
residue was used as such in the next step of the reaction sequence but it could be
crystallized from acetonitrile. Yield assumed to be 100%.
Compound (A11):
[0051] Compound (A10) (83.0 g, 111.26 mmol) was dissolved in tetrahydrofuran (800 mL) and
the solution stirred at room temperature. N,N-4-diethylaniline (17.7 mL, 111.26 mmol)
was added followed by a solution of 12% phosgene in toluene (275 mL, 333.78 mmol).
The reaction mixture was stirred at room temperature for 15 minutes, concentrated
under reduced pressure and the residue used as such in the next step. The yield of
the product, compound (A11), was assumed to be 100%.
Compound (A12):
[0052] Compound (A11) as described above (111.26 mmol) was dissolved in dry pyridine (800
mL) and PMT (19.83 g, 111.26 mmol) added to the reaction solution. The mixture was
stirred at room temperature for 1 hour. It was then concentrated under reduced pressure
and the residue 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 the ratio
of 20:20:56.4, respectively and subjected to flash chromatography eluting with the
same solvent system to elute impurities from the column and then changed to a ratio
of 27:50:20.4 to elute the product, compound (A12). The product could be recrystallized
from acetonitrile. Yield 61.0 g (58%).

Compound (A13):
[0053] Compound (A8) (4.0 g, 6.53 mmol) was suspended in dry ether (30 mL) and phosphorous
tribromide (0.68 mL, 7.18 mmol) in ether (20 mL) added dropwise over a 15 minute period.
After the addition the reaction was diluted with ether and the ether solution washed
with 2N-HCl (X1), dried (MgSO₄), filtered and concentrated to give compound (A13).
The yield was 100%.
Compound (A14):
Synthesis Example B: -
Compound (B16):
[0055] Compound (A3) (3.4 g, 14.83 mmol) was dissolved in deoxygenated dimethylsulphoxide
(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 minutes and then
the 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 continued for 2.5 hours.
While still at 60°C the warm solution was poured into ice cold 2N-HCl (600 mL). The
yellow product was filtered off, washed with water, methanol and air dried. Yield
of compound (B16) 8.8 g (89%).
Compound (B17):
[0056] Compound (B16) (8.8 g, 13.24 mmol) was dissolved in tetrahydrofuran (40 mL) to which
was added methanol (20 mL) and water (20 mL). Sodium borohydride (0.5 g, 13.24 mmol)
was added to the suspension portionwise with stirring. At the end of the addition
dissolution was complete and the solution stirred continually for a further 15 minutes.
The reaction solution was then poured into ice cold 2N-HCl (600 mL) and the product
compound (B17) filtered off, washed with water, methanol and air dried. Yield 7.9
g (89%).
Compound (B18):
[0057] Compound (B17) (10.0 g, 15.0 mmol) was suspended in water (70 mL) and 85%-potassium
hydroxide (7.90 g, 120.0 mmol) added together with methanol (20 mL). This mixture
was stirred at 80°C for 1 hour, cooled and poured into ice cold 2N-HCl and the mixture
extracted with ethyl acetate (X2). The combined ethyl acetate extracts were then dried,
(MgSO₄), filtered and concentrated. The residue compound (B18) was used as such in
the next step of the reaction sequence. Yield (100%).
Compound (B19):
[0058] Compound (B18) (15 mmol) was dissolved in ether (70 mL) and phosphorous tribromide
(1.6 mL, 16.5 mmol) in ether (15 mL) added dropwise over a period of 15 minutes. At
the end of the addition the reaction solution was stirred at room temperature for
a further 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), sufficiently pure to be used in the next step. Yield 100%.
Compound (B20):
[0059] Compound (B19) (15.0 mmol) was dissolved in dimethylformamide (50 mL) and treated
with sodium PMT (3.55 g, 17.73 mmol) while stirring at room temperature for a 1 hour
period. 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 subjected
to flash chromatography eluting with the same solvent mixture. The first major band
was collected to give the product compound (B20). Yield 5.0 g [42% from compound (B17)].

[0061] The following examples further illustrate the invention.
Examples 1 - 3:
[0062] Photographic elements were prepared by coating the following layers on a cellulose
ester film support (amounts of each component are indicated in mg/m²):
- Emulsion layer 1:
- Gelatin -2420; red sensitized silver bromoiodide (as Ag) - 1615; yellow image coupler
dispersed in dibutyl phthalate (RECEIVER LAYER)
- Interlayer:
- 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-diethyl-dodecanamide
and coated at a level sufficient to provide a contrast of 0.5 (half) of the original
contrast after stepwise green light exposure and processing.(CAUSER LAYER)
- Protective Overcoat
- Gelatin - 5380; bisvinylsulfonylmethyl ether at 2% total gelatin.
Structures of the image couplers are as follows:

[0063] Strips of each element were exposed to green light through a graduated density step
tablet, or through a 35% modulation fringe chart for sharpness measurements, and then
developed 3.25 minutes at 38°C in the following color developer, stopped, washed,
bleached, fixed, washed and dried.

[0064] Processed images were read with green light to determine the contrast and AMT acutance.
From plots of AMT acutance vs. the logarithm of the contrast for variations in the
coated level of each development inhibitor releasing (DIR) compound, the acutance
was determined at a contrast of 0.5 compared to its original contrast without the
presence of the DIR compound. The acutance for the control DIR coupler was subtracted
from each AMT value to provide the relative sharpness value reported as change in
AMT in Table I. AMT calculations employed the following formula in which the cascaded
area under the system modulation curve is shown in equation (21.104) on page 629 of
the "Theory of the Photographic Process", 4th Edition, 1977, edited by T.H. James:
AMT = 100+66Log[cascaded area/2.6696M] wherein th magnification factor M is 3.8 for
the 35mm system AMT. The use of CMT acutance is described by R.G. Gendron in "An Improved
Objective Method of Rating Picture Sharpness: CMT acutance" in the Journal of SMPTE,
Vol. 82, pages 1009-12, (1973). AMT is a further modification of CMT useful for evaluating
systems which include the viewing of a positive print made from a negative.

[0065] Compared to the control coupler the couplers of Examples 1 - 3 provide improved acutance
and interimage effects.
Example 4:
[0066] A photographic film was prepared, exposed and processed like the film in Examples
1 - 3. The processed images were read with green light to determine the contrast.
From plots of the logarithm of the contrast compared to the coated level of each DIR
coupler, the 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 its original
contrast without the presence of the DIR coupler. The smaller the amount of the DIR
compound required, the higher was the reactivity of the DIR coupler. Coupler 3 was
as described in Example 3. The results are given in following Table II:
