[0001] This invention relates to photographic materials and processes which utilize a compound
capable of releasing a bleach accelerator moiety.
[0002] Photographic materials useful for forming dye images by means of a process which
includes a bleaching step are known and used commercially. Such materials and processes
are described in, for example, The Theory of the Photographic Process, 4th Edition,
Edited by T.H. James, 1977, pages 462-463 and pages 335-361. The use in such photographic
materials of a bleach accelerator releasing coupler is described in Research Disclosure,
1973, Item No. 11449. The bleach accelerator releasing coupler, also known as a BARC,
has contained a heterocyclic group as the bleach accelerator moiety which is released
during processing of the photographic element. These bleach accelerator releasing
couplers cause an undesired degree of adverse development effects.
[0003] Couplers which have a thioether group at the coupling position have been known in
the photographic art. Examples of such couplers are described in, for example, U.S.
Patent 3,227,554 and U.S. Patent 4,293,691. These compounds have been useful as development
inhibitor releasing (DIR) couplers. Almost all of the couplers that are designed as
development inhibitor releasing couplers have a thioether group and are oleophilic
in order to help maintain the coupler in one location in the hydrophilic emulsion
layers of the photographic material. Typically such couplers have ballast groups for
this purpose. These have not required a balance of a strong affinity for silver and
a balance of water solubility as is the case with bleach accelerator compounds.
[0004] It has been found that a bleach accelerator releasing compound, particularly a coupler,
in a dye-forming photographic silver halide material, wherein the compound has a releasable
bleach accelerator moiety represented by the moiety:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0001)
wherein
TIME is a timing group;
n is 0 or 1;
R1 is a linking group, preferably alkylene comprising 1 to 8 carbon atoms or
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0002)
L' is alkylene containing 1 to 8 carbon atoms or phenylene; and
R2 is a water solubilizing group, preferably a carboxy group;
enables desired bleaching of silver in such photographic materials upon exposure and
processing.
[0005] The releasable bleach accelerator moiety is in a location on the compound carrying
the moiety which enables release of the bleach accelerator moiety at a time during
processing of the photographic element which enables acceleration of the bleaching
step. The bleach accelerator releasing compound is preferably a coupler having the
bleach accelerator moiety in the coupling position. The coupler can be, but need not
be, a dye-forming coupler.
[0006] One embodiment of the invention is a silver halide photographic element containing
a bleach accelerator releasing compound which has a releasable bleach accelerator
moiety as described. Another embodiment of the invention comprises in a color development
process which includes a silver bleaching step, the improvement comprising carrying
out the bleaching step in the presence of a bleach accelerator moiety released from
a bleach accelerator releasing compound, preferably a bleach accelerator releasing
coupler, as described.
[0007] Herein the term "coupler" refers to the entire compound including the coupler moiety
and the bleach accelerator moiety (TIME)
n-S-R
1-R
2. The term coupler moiety herein refers to that portion of the compound other than
the bleach accelerator moiety.
[0008] The particular R
1 group linking the sulfur atom and the water solubilizing group R can be varied to
control such parameters as water solubility, diffusivity, silver affinity, silver
ion complex solubility, silver development effects and other sensitometric effects.
Since these parameters can be controlled by modification of R
1, they need not be emphasized in selecting a particular coupler moiety and the particular
water solubilizing group, but provide freedom in selecting such moieties and groups
for a particular photographic element and process.
[0009] In processing, the bleach accelerator fragment is released at an appropriate time
as a unit. That is, -S-Rl-R2 is released as a unit. The rate and total time of diffusion
of the bleach accelerator fragment in the photographic element must be such as to
enable bleach acceleration in the appropriate layers of the photographic element during
processing. The timing group, when present, also releases -S-R
1-R
2 as a unit. Selection of R
1 and R
2 can also influence the rate and total time of release of the bleach accelerator moiety
from the remainder of the compound, preferably the remainder of the coupler. It is
necessary that the bleach accelerator moiety not adversely affect the processing steps
and the photographic element. Selection of a sufficiently water soluble bleach accelerator
moiety by selection of optimum R
1 and R
2 groups minimizes development inhibition activity of the bleach accelerator moiety
while enhancing bleach accelerator activity. This helps separate those compounds which
are useful bleach accelerator releasing compounds from those compounds which are useful
development inhibitor releasing compounds.
[0010] Preferred photographic couplers of the invention are repesented by the formula:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0003)
wherein
COUP is a coupler moiety;
m is I to 8;
R3 and R4 are individually hydrogen or alkyl containing 1 to 4 carbon atoms; and wherein the
total number of carbon atoms in
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0004)
is 1 to 8.
[0011] Alkyl includes straight or branched chain alkyl, such as methyl, ethyl, n-propyl,
i-propyl, n-butyl, and t-butyl.
[0012] The coupler moiety can be any moiety that will react with oxidized color developing
agent to enable release of the bleach accelerator moiety. The coupler moiety includes
coupler moieties which are useful in conventional dye-forming couplers which yield
dyes on reaction with oxidized color developing agents as well as coupler moieties
which yield colorless products on reaction with oxidized color developing agents.
[0013] The coupler moiety can be unballasted or ballasted with an oil-soluble group. It
can be monomeric, or it can form part of a dimeric, oligomeric or polymeric coupler,
in which case more than one bleach accelerator moiety can be contained in the coupler.
Each coupling position can release a bleach accelerator moiety.
[0014] It will be appreciated that, depending upon the particular coupler moiety, the particular
color developing agent and the type of processing, the reaction product of the coupler
moiety and oxidized color developing agent can be: (1) colored and nondiffusible,
in which case it will remain in the location where it is formed; (2) colored and diffusible,
in which case it may be removed during processing from the location where it is formed
or allowed to migrate to a different location; or (3) colorless and diffusible or
nondiffusible, in which case it will not contribute to image density. In cases (2)
and (3) the reaction product may be initially colored and/or nondiffusible but converted
to colorless and/or diffusible products during the course of processing.
[0015] The bleach accelerator moiety is attached at the coupling position of the coupler
moiety which enables the bleach accelerator moiety to be displaced upon reaction of
the coupler with oxidized color developing agent.
[0016] In bleach accelerator releasing organic compounds as described, preferably bleach
accelerator releasing couplers, the bleach accelerator moiety can be bonded to the
remainder of the organic compound through a timing group (TIME). TIME in the described
structures is a group which enables the timed release of -S-R
1-R
2 from COUP. The timing mechanism can be any timing mechanism which is useful for releasing
photographically useful groups from coupler moieties. For example, the timing mechanism
can be as described in, for example, U.S. Patent 4,248,962 or U.S. Patent 4,409,323.
[0017] Release of the bleach accelerator moiety can involve a single reaction or it can
involve sequential reactions. For example, two or more sequential reactions may be
required within a TIME group to effect release of the bleach accelerator moiety. As
another example, the TIME group can have two bleach accelerator moieties bonded to
different locations on the TIME group so that upon release of the TIME group from
the coupler moiety two reactions can occur sequentially enabling sequential release
of the two bleach accelerator moieties. Another example is a reaction in the TIME
group which may release a second coupler moiety which contains another timing group
to which a photographically useful group is attached and from which it is released
after the second coupler moiety reacts with oxidized color developing agent.
[0018] The TIME group can contain moieties and substituents which will permit control of
one or more of the rates of reaction of COUP with oxidized color developing agent,
the rate of diffusion of -TIME-S-RI-R2 once it is released from COUP and the rate
of release of -S-R
1-R
2. The TIME group can contain added substituents, such as added photographically useful
groups which can remain attached to the timing group and be released independently.
The TIME groups can contain a ballast group.
R2 can optionally be a precursor to a water solubilizing group. For example, R2 can be an ester group which upon hydrolysis forms a water solubilizing carboxylic
acid group.
[0021] The following is a listing of patents and publications which describe representative
COUP groups useful in the invention. In these structures the unsatisfied bonds in
each of the COUP groups show the point of attachment to TIME or, should no TIME group
be present, then to the bleach accelerator moiety; the vertical unsatisfied bond in
TIME shows the point of attachment of COUP and the horizontal unsatisfied bond in
TIME shows the point of attachment of the bleach accelerator moiety.
1. COUP'S
[0022] A. Useful couplers which form cyan dyes upon reaction with oxidized color developing
agents are described in such representative patents and publications as: U.S. Patent
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; and 4,666,999.
[0023] Preferably such couplers are phenols and naphthols which form cyan dyes on reaction
with oxidized color developing agents and have the releasable bleach accelerator moiety
attached at the coupling position, that is the carbon atom in the 4-position of the
coupler moiety. Structures of preferred cyan-dye-forming coupler moieties are:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0028)
wherein
R8, R9, R10, R11 and R12 individually represent ballast groups;
R7 and R9, individually represent at least one halogen atom, such as chloro or fluoro;
alkyl, such as alkyl containing 1 to 4 carbon atoms, for example methyl, ethyl, propyl
or butyl; or alkoxy, such as alkoxy containing 1 to 4 carbon atoms, for example methoxy,
ethoxy, propoxy and butoxy.
[0025] B. Examples of couplers which form magenta dyes upon reaction with oxidized color
developing agents are described in such representative patents and publications as:
U.S. Patent Nos. 2,600,788; 2,369,489; 2,343,703; 2,311,082; 3,152,896; 3,519,429;
3,062,653; and 2,908,573.
[0026] Preferably such magenta dye-forming couplers are pyrazolones and pyrazolotriazoles
which form magenta dyes upon reaction with oxidized color developing agents. Structures
of preferred magenta dye-forming couplers are:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0044)
wherein
R14, R16 and R17 are individually aryl, alkyl, such as alkyl containing 1 to 30 carbon atoms; and
R13, R15 and R18 are individually ballast groups, or are phenyl or substituted phenyl, such as 2,4,6-trihalophenyl,
for example, 2,4,6-trichlorophenyl.
[0028] C. Couplers which form yellow dyes upon reaction with oxidized color developing agents
are described in such representative patents as: U.S. Patent Nos. 2,875,057; 2,407,210;
3,265,506; 2,298,443; 3,048,194; and 3,447,928.
[0029] Preferably such yellow dye-forming couplers are acylamides, for example, benzoylacetanilides
and pivalylacetanilides.
[0030] Examples of such yellow dye-forming couplers are:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0052)
wherein
R21, R23 and R25 are individually ballast groups; and
R19, R20, R22 and R24 are individually hydrogen or one or more halogen, such as chlorine and fluoride;
alkyl, such as alkyl containing 1 to 4 carbon atoms, for example methyl, ethyl, propyl
and butyl; alkoxy, such as alkoxy containing 1 to 20 carbon atoms; or a ballast group.
[0032] D. Couplers which form colorless products or form products which do not significantly
absorb electromagnetic radiation within the visible range of the spectrum are described
in such representative patents as: U.K. 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 on reaction with oxidized color
developing agents.
[0033] Structures of representative couplers which form colorless products are:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0063)
wnerein
R26, R27, R28, R29 and R30 are individually ballast groups; m is 1 or 2.
[0035] Other colorless couplers are also useful, such as oxazolinones, for example,
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0070)
wherein R
30, is:
-CH2-COOH
-CH2CH2-COOH
-CH2CH2CH2-COOH
-CH2CH2CH2CH2-COOH
-CH2CH2OH
-CH2CH2SO3H
-CH2CH2SO2NH2
-CH2CH2CH2SO2NH2
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0071)
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0072)
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0073)
[0036] E. Couplers which form black dyes upon reaction with oxidized color developing agents
are described in such representative patents as: U.S. Patent Nos. 1,939,231; 2,181,944;
2,333,106; 4,429,035; 4,439,518; 4,254,213; 4,387,158; 4,126,461; and 4,200,466.
[0037] Preferably such couplers are resorcinols or m-aminophenols which form black products
on reaction with oxidized color developing agents. Structures of preferred couplers
capable of forming a black dye are:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0076)
wherein
R31 and R32 are individually alkyl, such as alkyl containing 3 to 20 carbon atoms, phenyl or
phenyl substituted with hydroxy, halo, such as chloro or bromo, amino, alkyl, such
as alkyl containing 1 to 20 carbon atoms, or alkoxy, such as alkoxy containing 1 to
20 carbon atoms; and
R33 and R34 are individually hydrogen, alkyl, such as alkyl containing 1 to 20 carbon atoms,
alkenyl, such as alkenyl containing 1 to 20 carbon atoms, or aryl, such as aryl containing
6 to 20 carbon atoms; and,
R35 is one or more halogen, such as chlorine or bromine, alkyl, such as alkyl containing
1 to 20-carbon atoms, alkoxy, such as alkoxy containing 1 to 20 carbon atoms, or other
monovalent organic groups that do not adversely affect the dye formation or release
of the bleach accelerator moiety.
[0040] TIME groups which are useful enable release of the bleach accelerator moiety at the
appropriate time during processing, that is at the time which enables accelerated
bleaching of the photographic element. Examples of such TIME groups are:
A. Acyclic TIME groups:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0080)
wherein n is 1 to 4;
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0081)
R36 is hydrogen, alkyl, such as alkyl containing 1 to 20 carbon atoms; or aryl, such
as aryl containing 6 to 20 carbon atoms, preferably unsubstituted phenyl or substituted
phenyl.
B. Aromatic TIME groups:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0082)
wherein n is 0 or 1;
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0083)
R31 is hydrogen, alkyl, such as alkyl containing 1 to 20 carbon atoms; or aryl, such
as aryl containing 6 to 20 carbon atoms, for example, phenyl;
X is hydrogen; cyano; fluoro; chloro; bromo; iodo; nitro; alkyl, such as alkyl containing
1 to 20 carbon atoms; preferably methyl, ethyl, propyl or butyl; or aryl, such as
aryl containing 6 to 20 carbon atoms, preferably unsubstituted phenyl or substituted
phenyl.
[0041] The bleach accelerator releasing coupler can be used in combination with a colorless
coupler or a colored coupler and added to a silver halide emulsion together with an
image dye-forming coupler, or alternatively in the form of an independent emulsion
in an auxiliary layer, such as an intermediate layer and/or an undercoat layer. The
bleach accelerator releasing compounds are useful alone or in combinations of two
or more bleach accelerator releasing compounds.
[0042] The bleach accelerator releasing couplers can be incorporated in photographic elements
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.
[0043] Photographic elements in which the photographic couplers 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 coupler compounds of this invention
can be incorporated in the silver halide emulsion layer or in another 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 development inhibitor releasing (DIR) couplers, color forming
couplers and colored masking couplers. These other photographic coupler compounds
can form dyes of the same or different color and hue as the bleach accelerator releasing
compounds. Additionally, the silver halide emulsion layer can contain addenda conventionally
contained in such layers.
[0044] A typical multilayer, multicolor photographic element according to this invention
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 bleach accelerator releasing compound 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.
Typical arrangements are described in U.S. Patent Nos. 3,227,554; 3,620,747; 3,843,369;
and U.K. Patent No. 923,045. The coupler compounds of this invention can be incorporated
in or associated with one or more layers or units of the element. The layer(s) and
unit(s) affected by the bleach accelerator moiety can be controlled by incorporating
in appropriate locations in the element scavenger layer(s) which will confine the
action of the bleach accelerator moiety to the desired layer(s) or unit(s).
[0045] 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 emulsion can be negative-working
or a direct-positive emulsion. They can form latent images predominantly on the surface
of the silver halide grains or predominantly in the interior of the silver halide
grains. They can be chemically and spectrally sensitized. The emulsions typically
will be gelatin emulsions although other hydrophillic colloids can be used in accordance
with usual practice. Tabular grain photographic silver halide emulsions, described
in, for example, Research Disclosure, January 1983, Item No. 22534 and U.S. Patent
4,434,226 are particularly useful.
[0046] 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, flexible support is employed,
such as a polymeric film or paper support. Paper supports can be acetylated or coated
with baryta and/or an a-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.
[0047] If the coupler moiety is a dye-forming coupler, it can react with oxidized developing
agent in the same or an adjacent layer to form a dye of the same or different color
or hue as that obtained from the primary coupler. If the coupler moiety is a competing
coupler, it can react with oxidized color developing agent in the same or an adjacent
layer to reduce dye density.
[0048] The optimum concentration range of bleach accelerator releasing compound will depend
upon such factors as the desired image, the location of the bleach accelerator releasing
compound, processing conditions, the particular bleach composition, the particular
layers of the photographic element, processing steps and the particular bleach accelerator
moiety. A typical concentration of bleach accelerator releasing compound in a photographic
element is within the range of about 50 to about 500 mg/sq meter.
[0049] A particularly useful photographic element according to the invention is a dye-forming
photographic element having a layer format known to be useful in forming a multicolor
image by a subtractive coror process. Any or all of the respective color records can
be in the form of a double or triple layer structure.
[0050] The process of forming a dye image in a photographic element as described comprises
conventional color processing involving a bleaching step. The bleaching step is preferably
conducted separately from fixing. The bleaching composition comprises known bleaching
agents. Examples of typical processes are described in Research Disclosure, December
1978, Item No. 17643 and in "Modern Photographic Processing", by Grant Haist, Vol.
2, pages 569-587, John Wiley and Sons, N.Y., 1979. Processing of a dye-forming photographic
element according to the invention typically comprises a color development step, a
bleaching step and a fixing step. The bleaching step and fixing step can be combined
into one step if desired. Other processing steps which are also useful in this process
include a pre-hardening step, a neutralization step, a first development step (black-and-white
development), a stabilizing step, and water washing step. Processing steps are typically
carried out at a temperature within the range of 18°C to 60°C.
[0051] The bleach accelerator releasing compounds are prepared by organic synthesis procedures
known in the organic compound synthesis art. For example, the coupler moiety can be
reacted with the bleach accelerator moiety in an appropriate solvent. The following
are representative preparations of bleach accelerator releasing couplers:
Synthesis Example A:
[0052] This relates to the synthesis of the following bleach accelerator releasing coupler:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0084)
[0053] A solution of 20 g (33 mmol) of the following compound (coupler moiety):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0085)
5.8 g (33 mmol) of 1-(2-carboxyethyl) tetrazoline-5-thione (bleach accelerator moiety),
and 14 g of potassium carbonate (K
2CO
3) in 500 mL of dimethylformamide (solvent) are heated 2 hours at 80°C. The resulting
composition is then cooled and drowned in ice cold dilute hydrochloric acid. The resulting
product is isolated and purified. This can be done by extraction and then purification
by silica gel chromotography and recrystallization from acetonitrile to yield a nearly
colorless product which is identified by elemental analysis as the desired bleach
accelerator releasing coupler.
Synthesis Example B:
[0054] This relates to the synthesis of the following bleach accelerator releasing coupler:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0086)
[0055] To a solution of 5.6 g (8 mmol) of the coupler moiety:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0087)
(prepared by procedures described in U.S. Patent 4,248,962) is added 1.1 g (8 mmol)
of 2-dimethyl- aminoethanethiol hydrochloride represented by the formula:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0088)
in 25 mL of dry pyridine. The mixture is stirred overnight and then drowned in water.
The resulting product is then extracted and purified. The desired product can be isolated
by ethyl acetate extraction, triturated with ligroin and dried to obtain the desired
bleach accelerator releasing coupler having a melting point of 130-131°C, and which
is identifed by spectral and elemental analysis.
Synthesis Example C:
[0056] This relates to the synthesis of the bleach accelerator releasing coupler:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0089)
[0057] To a solution of 5g (9.9 mmol) of the coupler moiety:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0090)
in 75 mL of tetrahydrofuran, stirred under nitrogen, is added 1.4 g (9.9 mmol) of
tetramethylguanidine and then 1.1 mL (9.9 mmol) of ethyl acrylate. After 30 minutes
50 mL of methanol and 10 mL of 1.25 N sodium hydroxide solution are added and the
resulting composition stirred for 15 minutes. The mixture is then drowned in ice-cold
dilute hydrochloric acid. The desired product is extracted and purified. For example,
the desired product is extracted with diethyl ether to obtain, after crystallization,
the desired bleach accelerator releasing coupler which is a colorless solid having
a melting point of 139°C to 141°C. The product is also identified by elemental and
spectral analysis.
Synthesis Example D:
[0058] This relates to the synthesis of the bleach accelerator releasing coupler:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0091)
[0059] To a stirred solution of 20 g (70 mmol) of the compound
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0092)
and 7.4 g (70 mmol) 3-mercaptopropionic acid (HSCH
lCH2COOH) in 75 mL of dimethylformamide is added, dropwise, 3.85 mL of bromine in 25
mL of dimethylformamide. After stirring overnight the mixture is drowned in water.
A single product, designated as P-2:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0093)
is isolated by filtration. Next, 11 g of zinc is added to a solution of 5.6 g (13.7
mmol) of P-2 in 200 mL of glacial acetic acid and stirred 30 minutes before filtration.
Then 6.9 g (13.7 mmol) of the compound, designated as P-3:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0094)
is added to the filtrate, stirred for 1 hour and the mixture poured into water. The
resulting product isolated by extraction, is then dissolved in methanol/tetrahydrofuran
(equal parts by volume), then hydrolyzed with 50% sodium hydroxide solution, and acidified
with cold excess dilute hydrochloric acid. The desired bleach accelerator releasing
coupler is then extracted and purified by silica gel chromatography. This bleach accelerator
releasing coupler has a melting point of 120-122°C and is identified by elemental
analysis indicating one water of hydration is present.
[0060] The following examples further illustrate the invention:
Example 1
[0061] This illustrates a multilayer color photographic element comprising a bleach accelerator
releasing coupler according to the invention.
[0062] A multilayer color photographic element, designated herein as Sample a, was prepared
by coating the following layers on a cellulose triacetate film support in the designated
order (levels coated are given in mg/m
2 with silver halide stated as silver level):
Layer 1: Slow Cyan Layer-(bottom Slow, red-sensitized silver bromoiodide layer) tabular
grain gelatino emulsion (1615 mg/m2), gelatin (2153 mg/m2). This layer also comprises a cyan image dye-forming coupler, designated as C-1 (603
mg/m2):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0095)
and a colored coupler (65 mg/m2), designated as C-3 and described below, as well as a development inhibitor releasing
coupler, designated as D-1 (43 mg/m2):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0096)
Layer 2: Fast Cyan Layer-Fast red-sensitized silver bromoiodide tabular-grain gelatino
emulsion, prepared as described in U.S. Patent 4,434,226 of Wilgus. This layer also
comprises gelatin (1615 mg/m2) and a cyan image dye-forming coupler, designated as C-2 (194 mg/m2):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0097)
and a colored coupler, designated as C-3 (16 mg/m2):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0098)
Layer 3: Interlayer-Gelatin (1292 mg/m2)
Layer 4: Slow Magenta Layer-Green sensitized silver bromoiodide tabular-grain gelatino
emulsion, prepared as described in U.S. Patent 4,434,226 of Wilgus. This layer also
comprises a magenta image dye-forming coupler, designated as coupler M-1:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0099)
and a colored coupler, designated as M-3:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0100)
as well as a development inhibitor releasing coupler, designated as DIR coupler D-2:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0101)
Layer 5: Fast Magenta Layer-Fast green-sensitized silver bromoiodide tabular-grain
gelatino emulsion prepared as described in U.S. Patent 4,434,226 of Wilgus. This layer
also comprises a magenta image dye-forming coupler, designated as coupler M-2:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0102)
and a colored coupler, designated as M-3:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0103)
Layer 6: Interlayer-Gelatin
Layer 7: Slow Yellow Layer-Blue-sensitized silver bromoiodide tabular-grain gelatino
emulsion (3 to 6 mol % iodide) prepared as described in U.S. Patent 4,434,226 of Wilgus.
This layer also comprises yellow image dye-forming coupler Y-1 and a development inhibitor
releasing coupler (DIR coupler):
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0104)
and a gelatin hardener
Layer 8: Fast Yellow Layer-Fast, blue-sensitized silver bromoiodide gelatino emulsion
as described in U.S. Patent 3,320,069 of Illingsworth, and optimally sensitized with
sulfur and gold. This layer also contains a yellow image- dye-forming coupler designated
as coupler Y-1:
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0105)
Layer 9: Protective Overcoat-Blend of U.V. absorbers and gelatin
[0063] Samples b, d, f, and h were prepared in the same manner as for Sample a except that
coupler C-2 in Layer 2 was replaced by the amounts indicated in Table 1 of comparison
coupler C-4, and bleach accelerator releasing couplers designated as BARC-1, -2, or
-3, respectively. Further, Samples c, e, g, and i were similarly prepared by replacing
half of coupler C-1 in Layer 1 of Sample a by the indicated amounts of comparison
coupler C-4 and BAR couplers 1, 2, or 3, respectively. These samples were each given
a white light exposure through a graduated density step tablet and processed for 3.25
minutes in a color developer of the type described in the British Journal of Photography
Annual, 1979, pp. 204-206. From plots of density to red light vs. log exposure the
D-min, D-max, and relative photographic speed AS (in log E units at D = fog + 0.1)
were determined as reported in Table A. The residual silver remaining after the bleach
step was determined by x-ray fluorescence measurement and the average for the two
highest exposure steps is given in Table A.
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0106)
[0064] The data in Table A show that addition of BARC-1, -2, or -3 to cyan layers of the
multilayer element improves the removal of silver which otherwise would be retained
causing color reproduction problems. When added to the fast layer at relatively high
levels BARC-1 and -2 give substantial speed losses while for BARC-3 such loss is minimal.
All except BARC-2 when added to the slow layer increase the minimum density.
[0065] Comparison C-4 herein is:
[0066]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0107)
BARC-1 herein is:
[0067]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0108)
BARC-2 herein is:
[0068]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0109)
BARC-3 herein is:
[0069]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0110)
Example 2
[0070] Multilayer incorporated coupler photographic elements were prepared in the same manner
as for Sample a of Example 1, with coated amounts given in mg/m
2. Control Sample j was coated as follows on the film support:
Layer 1: Slow Cyan Layer-(bottom Comprising a red-sensitized silver layer) bromoiodide
tabular-grain emulsion blend (1615), gelatin (2153), cyan image coupler C-1 (603),
colored coupler C-3 (32), and DIR coupler D-1 (32).
Layer 2: Fast Cyan Layer-Comprising a fast red-sensitized silver bromoiodide tabular-grain
emulsion (1076), gelatin (1615), cyan image coupler C-2 (151), and colored coupler
C-3 (48).
Layer 3: Interlayer-Comprising gelatin (1292).
Layer 4: Slow Magenta Layer-Comprising a green-sensitized silver bromoiodide tabular-grain
emulsion blend (1292), gelatin (1615), magenta image coupler M-1 (646), colored coupler
M-3 (43), and DIR coupler D-2 (13).
Layer 5: Fast Magenta Layer-Comprising a fast green-sensitized silver bromoiodide
tabular-grain emulsion (969), gelatin (1292), magenta image coupler M-2 (108), and
colored coupler M-3 (46).
Layers 6 through 9 were the same as for Sample a, Example 1. Sample k was prepared
as for Sample j but with the following changes in the magenta layers:
Layer 4: Coupler M-l (484), coupler D-2 (32), and added bleach accelerator releasing
coupler designated as BARC-4 (108).
Layer 5: Coupler M-2 (54) and added BARC-4 (54). Sample 1 was prepared as for Sample
j but with the following changes in the cyan layers:
Layer 1: Coupler C-1 (517) and added BARC-3 (86).
Layer 2: Coupler C-2 (75) and added BARC-3 (60).
[0071] Sample m was prepared as for Sample j but adding bleach accelerator releasing couplers
to both cyan and magenta layers 1, 2, 4, and 5 according to the changes indicated
in preparing Samples k and 1.
[0072] Photographic results after exposure and processing as in Example 1 are shown in Table
B, where R, G, and W indicate samples were given red, green, or white light exposures,
respectively.
BARC-4 herein is:
[0073]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0112)
[0074] The following examples can be carried out according to Example 1 with the exception
that the bleach accelerator releasing coupler is replaced by the bleach accelerator
releasing coupler designated in the following examples:
Example 3
BARC-5 herein is:
[0075]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0113)
Example 4
BARC-6 herein is:
[0076]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0114)
Example 5
BARC-7 herein is:
[0077]
![](https://data.epo.org/publication-server/image?imagePath=1986/36/DOC/EPNWA2/EP86301365NWA2/imgb0115)