Photographic material and process comprising a pyrazoloazole dye-forming coupler

Novel pyrazoloazole dye-forming couplers comprising (I) at least one polyether group (A) comprising at least two ether (--O--) groups and (II) having between the group (A) and the pyrazoloazole nucleus a linking group (L) that is capable of increasing the reactivity of the coupler to enable improved dye images in a photographic element and process. These couplers are useful in photographic silver halide elements and processes.

This invention relates to novel pyrazoloazole dye-forming couplers and to 
photographic silver halide materials and processes using such couplers. 
Color images are customarily obtained in the photographic art by reaction 
between the oxidation product of a silver halide developing agent and a 
dye-forming coupler. Pyrazolone couplers are useful for forming magenta 
dye images; however, pyrazoloazole couplers, particularly pyrazolotriazole 
couplers, represent another class of couplers that are useful for this 
purpose. Examples of pyrazolotriazole couplers, particularly 
pyrazolo-[3,2-c]-s-triazole couplers, are described in, for instance, U.S. 
Pat. No. 4,443,536; U.K. Patent Nos. 1,247,493; 1,252,418 and 1,398,979; 
and U.S Pat. Nos. 4,665,015; 4,514,490; 4,639,413; and 4,639,415. An 
example of such a pyrazolotriazole coupler is represented by the formula: 
##STR1## 
While such magenta couplers are useful in photographic silver halide 
materials and processes, many such couplers do not have sufficient coupler 
reactivity. It has been desirable to provide a pyrazoloazole coupler that 
has increased reactivity to provide increased maximum magenta image-dye 
density in color photographic silver halide materials and processes. 
It has been found that a novel pyrazoloazole dye-forming coupler enabling 
the described advantages comprises (I) at least one polyether group (A) 
comprising at least two ether (--O--) groups and (II) having between the 
group (A) and the pyrazoloazole nucleus a linking group (L). 
Such dye-forming couplers are particularly useful in photographic silver 
halide materials and processes. 
Pyrazolotriazoles are particularly useful pyrazoloazoles as described. Such 
pyrazolotriazoles include, for example, a 
1H-pyrazolo[2,3-b]-1,2,4-triazole or a 1H-pyrazolo[3,2-c]-s-triazole. A 
1H-pyrazolo[2,3-b]-1,2,4-triazole can also be named as a 
1H-pyrazolo[1,5-b]-1,2,4-triazole. The latter nonmenclature has neen used 
in the photographic art in, for example, U.S. Pat. No. 4,540,654. The 
group containing the polyether group (A) and the linking group as 
described in the case of a 1H-pyrazolo-[2,3-]-1,2,4-triazole is in the 
2-and/or 6-position and in the case of a pyrazolo[3,2-c]-s-triazole in in 
the 6- and/or 3-positions. 
It is believed that the combination of the polyether group (A) as described 
and the linking group enable a useful degree of water solubilization of 
the coupler that in turn enables the increased reactivity observed. The 
combination of these groups enables formation of higher maximum dye 
density from the coupler than is otherwise observed when only one of these 
groups is present on the pyrazoloazole nucleus of the coupler. The 
combination of the two groups enables tailoring of the reactivity of the 
coupler to a desired degree. For example, selection of the number of ether 
groups can be used to help tailor the degree of water solubility that the 
coupler has. The linking group on the other hand influences the polyether 
group and the coupler by enhancing the polar nature of the molecule, 
providing better reactivity with oxidized developer. 
A typical pyrazoloazole coupler as described is represented by the formula: 
##STR2## 
wherein 
COUP is a pyrazoloazole coupler nucleus, preferably a pyrazolotriazole 
coupler nucleus; 
R.sup.6 is hydrogen or unsubstituted or substituted alkyl, such as alkyl 
containing 1 to 30 carbon atoms, for example methyl, ethyl, propyl, 
n-butyl and t-butyl; aryl, such as phenyl; alkoxy, such alkoxy containing 
1 to 30 carbon atoms, such as methoxy, ethoxy, propoxy, and eicosyloxy; 
and aryloxy, such as phenoxy; and 
L.sup.1 is --NHCO, --NHSO.sub.2 --, --NHPO--R.sup.6A, --NHCONH--, 
--NHCO--R.sup.4 --, --NHSO.sub.2 --R.sup.4 --; 
R.sup.4 is unsubstituted or substituted alkylene, such as alkylene 
containing 1 to 2 carbon atoms, for example, methylene, ethylene, 
isopropylene, 
##STR3## 
phenethyl and benzyl. 
R.sup.6a is R.sup.6 or O-R.sup.7 ; and, 
R.sup.7 is a polyether group, preferably a polyether group containing at 
least two --OCH.sub.2 Ch.sub.2 -- groups. 
The linking group L.sup.1 is preferably bonded directly to the the 
pyrazoloazole coupler nucleus at a non-coupling site. A highly preferred 
coupler is a pyrazolo[3,2-c]-s-triazole having the linking group in at 
least one of the 3- and 6-positions. 
The polyether group can be terminated by any group that does not adversely 
affect the advantages of the coupler, for example an alkyl group, such as 
a methyl, ethyl, propyl, n-butyl, t-butyl or isopropyl, or aryl group, 
such as phenyl. It is often most useful to have the polyether group 
terminated by a water-solubilizing group, such as a carboxy, sulfonamide, 
alkyl alcohol, or phenol group. 
An especially useful pyrazoloazole coupler as described is a 
pyrazolo[3,2-c]-s-triaxole having a group (B) in at least one of the 3- 
and 6-positions represented by the formula: 
EQU --X--L.sup.2 --O--R.sub.1 --O--R.sub.2--.sub.n R.sub.3 --Z 
wherein n is 1 or 2; 
X is a bond or unsubstituted or substituted alkylene, such as alkylene 
containing 1 to 25 carbon atoms, such as methylene, ethylene, or decylene; 
or arylene, such as unsubstituted or substituted phenylene; 
L.sup.2 is a linking group selected from the group consisting of --NHCO--; 
--NHSO.sub.2 --; --NHCO--O--R.sup.4 --, and --NHCONH--R.sup.4 --; 
R.sub.1, R.sub.2, R.sub.3, and R.sup.4 are individually unsubstituted or 
substituted alkylene or arylene, as described; and 
Z is a water solubilizing group, such as carboxy, sulfonamide, alkyl 
alcohol, or phenol, or unsubstituted or substituted alkyl, such as alkyl 
containing 1 to 25 carbon atoms, for example, methyl, ethyl, propyl, 
n-butyl or t-butyl, or unsubstituted or substituted aryl, such as phenyl. 
Illustrative examples of useful couplers containing described linking 
groups and polyether groups are as follows: 
##STR4## 
The pyrazoloazole coupler typically contains, in a position that does not 
contain the described polyether and linking groups, hydrogen or a group 
that typically promotes solubility, diffusion resistance or dye hue of the 
dye formed from upon reaction of the coupler with the oxidized color 
developing agent. 
The pyrazoloazole coupler typically contains, in a position not containing 
the polyether and linking group, as described, hydrogen or a group 
selected from the following: amino, such as dioctylamino, dimethylamino, 
and dodecylamino; alkyl, such as alkyl containing 1 to 40 carbon atoms, 
for example methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, and 
dodecyl; cycloalkyl, such as cyclohexyl and cyclopentyl; aryl, such as 
aryl containing 6 to 30 carbon atoms, for example, phenyl, naphthyl and 
mesityl; carboxy; cyano; nitro; a heterocyclic group, such as a 
heterocyclic group comprised of atoms selected from carbon, oxygen, 
nitrogen, and sulfur atoms necessary to complete a five or six member 
ring, for example furyl, pyrrolyl, oxazolyl, thienyl, thiazolyl, and 
pyridyl; or --(L.sub.a).sub.w --(L.sub.b).sub.q --R.sub.6c wherein L.sub.a 
is a linking group that is the same as or different from the described 
linking groups and that does not adversely affect the desired properties 
of the coupler, such as an alkylene group, for example alkylene containing 
1 to 20 carbon atoms, including methylene, ethylene, propylene, 
n-butylene, isopropylmethylene, and octylene, or arylene, for example, 
phenylene and naphthylene; L.sub.b is also a linking group that is the 
same as or different from the described linking groups and that does not 
adversely affect the desired properties of the coupler, and is typically 
O, S, CO.sub.2, SO.sub.2, SO, NR.sub.7 CO, NR.sub.7 SO.sub.2, CONR.sub.7, 
NR.sub.7 SO.sub.2 NR.sub.8, SO.sub.2 NR.sub.7, O--CONR.sub.7, NR.sub.7 
CONR.sub.8 and N.sub.7 CO--O. R.sub.7 and R.sub.8 are individually 
hydrogen, alkyl, such as alkyl containing 1 to 30 carbon atoms, for 
example, methyl, ethyl, propyl, n-butyl, t-butyl and dodecyl, or aryl, 
such as aryl containing 6 to 30 carbon atoms, for example, phenyl and 
naphthyl; w and q are individually 0 or 1; and, R.sub.6c is alkyl, such as 
alkyl containing 1 to 30 carbon atoms, for example, methyl, ethyl, propyl, 
n-butyl, t-butyl and octyl, or aryl, such as aryl containing 6 to 30 
carbon atoms, for example phenyl, naphthyl and mesityl; or a heterocyclic 
group, such as a five or six member heterocyclic group comprised of atoms 
selected from carbon, oxygen, nitrogen and sulfur atoms necessary to 
complete a five or six member heterocyclic ring, such as an oxazole, 
pyridine, pyrrole or thiophene ring. 
These groups are unsubstituted or substituted with groups that do not 
adversely affect the desired properties of the pyrazoloazole coupler. 
Examples of useful substituents include ballast groups and coupler 
moieties that are known to be useful in the photographic art, or alkyl, 
such as alkyl containing 1 to 4 carbon atoms, for example, methyl, ethyl, 
and t-butyl. 
The pyrazoloazole contains in the coupling position, hydrogen or a 
coupling-off group, also known as a leaving group. 
Coupling-off groups are known to those skilled in the art. Such groups can 
determine the equivalency of the coupler, can modify the reactivity of the 
coupler, or can advantageously affect the layer in which the coupler is 
coated or other layers in the element by performing, after release from 
the coupler, such functions as development inhibition, development 
acceleration, bleach inhibition, bleach acceleration, color correction, 
and the like. Representative classes of coupling-off groups include 
halogen, particularly chlorine, bromine, or fluorine, alkoxy, aryloxy, 
heterocyclyloxy, sulfonyloxy, acyloxy, carbonamido, imido, acyl, 
heterocyclylimido, thiocyano, alkylthio, arylthio, heterocyclylthio, 
sulfonamido, phosphonyloxy and arylazo. They are described in, for 
example, U.S. Pat. Nos. 2,355,169; 3,227,551; 3,432,521; 3,476,563; 
3,617,291; 3,880,661; 4,052,212 and 4,134,766; and in U. K. patents and 
published application Nos. 1,466,728; 1,531,927; 1,533,039; 2,006,755A and 
2,017,704A; the disclosures of which are incorporated herein by reference. 
Examples of specific coupling-off groups are 
##STR5## 
--SCN, --OCH.sub.3, --OC.sub.6 H.sub.5, --OCH.sub.2 CONHCH.sub.2 CH.sub.2 
OH, --OCH.sub.2 CONHCH.sub.2 CH.sub.2 OCH.sub.3, --OCH.sub.2 CONHCH.sub.2 
CH.sub.2 OCOCH.sub.3, 
##STR6## 
The pyrazoloazoles typically comprise a ballast group. A ballast group as 
described is an organic radical 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. Couplers of the invention may be attached to ballast 
groups, or to polymeric chains through one or more of the groups on the 
pyrazoloazole nucleus. For example, one or more coupler moieties can be 
attached to the same ballast group. Representative ballast groups include 
substituted or unsubstituted alkyl or aryl groups containing 8 to 32 
carbon atoms. Representative substituents include alkyl, aryl, alkoxy, 
aryloxy, alkylthio, arylthio, arylthio, hydroxy, halogen, alkoxycarbonyl, 
aryloxycarbonyl, carboxy, acyl, acyloxy, carbonamido, carbamoyl, 
alkylsulfonyl, arylsulfonyl, sulfonamido, and sulfamoyl groups wherein the 
alkyl and aryl substituents and the alkyl and aryl portions of the alkoxy, 
aryloxy, alkylthio, arylthio, alkoxycarbonyl, arylcarbonyl, acyl, acyloxy, 
carbonamido, carboamoyl, alkylsulfonyl, arylsulfonyl, sulfonamido, and 
sulfamoyl substituents containing 1 to 30 carbon atoms and 6 to 30 carbon 
atoms, respectively, can be further substituted with such substituents. 
Particularly useful pyrazoloazole couplers are those that comprise a 
water-solubilizing group for some photographic materials that enables 
increased reactivity of the coupler. For example, a particularly useful 
coupler is a pyrazoloazole, as described, comprising a substituent, such 
as a ballast group, comprising at least one carboxy group. 
Particularly useful pyrazoloazole couplers are represented by the formula: 
##STR7## 
wherein 
Q is hydrogen or a coupling-off group, preferably chlorine; 
R.sup.5 and R.sup.6 are individually hydrogen or unsubstituted or 
substituted alkyl, alkoxy, aryl or aryloxy; 
R.sup.7 is a substituted or unsubstituted polyether group containing at 
least two ether (--O--) groups, preferably at least two ethyloxy groups 
[--Ch.sub.2 CH.sub.2 O--.sub.2 ]. 
Other particularly useful couplers are those represented by the above 
formula wherein R.sup.5 is optionally a substituted or unsubstituted 
polyether group containing at least two ether (--O--) groups, preferably 
at least two ethyloxy groups. 
Illustrative pyrazoloazole couplers containing the linking group and 
polyether group as described are as follows: 
##STR8## 
Pyrazoloazole couplers as described can be used in ways and for purposes 
that pyrazoloazole couplers have been used in the photographic art. 
Pyrazolazole couplers as described, particularly pyrazolotriazole couplers, 
are prepared by general methods of synthesis described in the art, such as 
in Research Disclosure, Aug. 1974, Item No. 12443 published by Kenneth 
Mason Publications, Ltd., The Old Harbourmaster's 8 North Street, 
Emsworth, Hampshire P010 7DD, England and U.S. Pat. No. 4,540,654. An 
illustrative synthesis Scheme I is as follows: 
##STR9## 
Examples of the synthesis of pyrazoloazole couplers as described are as 
follows: 
SYNTHESIS EXAMPLE A 
Synthesis of (2) 
2'-Hydroxyacetophenone (136 g, 1.0 mol) was dissolved in 1000 ml of acetone 
and 100 ml of H.sub.2 O and treated with 50% sodium hydroxide. A yellow 
solid is formed immediately and mechanical stirring is required. The 
iododocecane (296 g, 1.0 mol) is added in one portion and the reaction is 
heated at reflux with vigorous stirring for 2 days. All of the 
2'-Hydroxyacetophenone was consumed by thin layer chromatography and only 
one new product was formed. The reaction was cooled to room temperature 
(20.degree. C.) and partitioned with ligroin and water in a separatory 
funnel. The organic layer was washed with 10% NaOH twice and H.sub.2 O. 
The organic layer was dried (MgSO.sub.4) and concentrated. The product was 
placed in the refrigerator at about 5.degree. C. and crystallized. This 
material was collected and washed with methanol to form 205 g of the 
product (57%). More of the product was present in the mother liquors but 
was not recovered. The product (2) has an Mp of 29.degree.-31.degree. C. 
Synthesis of (3) 
Concentrated sulfuric acid (300 ml) was placed in a 2-liter erlenmeyer 
flask and cooled to 15.degree. C. by an ice bath and stirred mechanically. 
The acetophenone compound (2) was added portionwise maintaining the 
solution below 25.degree. C. The reaction was cooled to below 15.degree. 
C. and the aqueous nitric acid (27 g of 70% HNO.sub.3) was added dropwise 
with rapid stirring keeping the reaction temperature below 15.degree. C. 
(Note that higher temperatures during the reaction promote the formation 
of the 3'-nitro-2-dodecyloxyacetophenone which is a minor side product of 
the reaction.) The addition required 2 hours. The reaction was poured 
slowly into 2 liters of ice keeping the reaction throughly cooled until 
throughly mixed with water. The mixture was extracted with ethyl acetate 
and the organic layer was washed with water and saturated NaHCO.sub.3 and 
water again. The organic product was dried (MgSO.sub.4) and concentrated 
to a dark oil. This material was taken up in 300 ml of ligroin and seeded 
with some solid and placed in a freezer at about -5.degree. C. overnight. 
The solid was collected and washed with fresh cold ligroin and dried to 
give 66 g of product (3) (72%). 
Synthesis of (4) 
The 5'-nitro, 2'-dodecyloxyacetophenone (3) (76 g, 0.2 mol) was dissolved 
in 500 ml glacial acetic acid and neat bromine (35 g, 0.2 mol) was added 
dropwise over a 2-hour period, watching the temperature. The bromination 
appeared to generate no significant heat. After one equivalent of bromine 
was added the reaction was assumed complete because the products are hard 
to separate from the starting materials on thin layer chromatography. 
(Adding more bromine causes formation of the dibromoketone.) The reaction 
mixture was drowned out in water and extracted with ethyl acetate. The 
organic layer was washed with water and carefully washed with saturated 
NaHCO.sub.3 several times to remove all the acetic acid. The organic 
product was dried (MgSO.sub.4) and concentrated to yield a viscous 
yellow-brown oil. This product was carried on to the next step as is and 
was assumed to be complete for the next reaction. 
Synthesis of (6) 
The bromoketone (4) (85 g, 0.02 mol) and the aminothiodiazole (5) (38 g, 
0.2 mol) were mixed in methanol (300 ml) and heated at reflux under 
nitrogen for 4-6 hours until reaction was complete by thin layer 
chromatography. The reaction was concentrated and 300 ml ethyl acetate was 
added and the mixture again concentrated. This procedure was repeated 
until a solid was formed from the dark colored mixture. This solid 
material was collected and washed with 600 ml diethyl ether. This white 
solid hydrobromide salt was dissolved in methanol/ethyl acetate and 
treated with 10% sodium hydroxide. The organic layer was dried 
(MgSO.sub.4) and concentrated to a white solid (6) (Mp 
114.degree.-115.degree. C.) (Yield 85 g. 77%). 
Synthesis of (7) 
The thiadiazine (6) (50 g, 0.1 mol) was dissolved in acetic anhydride (200 
ml) and heated at reflux for 2 hours until the reaction was complete by 
thin layer chromatography. The reaction was allowed to cool to room 
temperature (20.degree. C. ) and concentrated, removing 1/3 to 1/2 of the 
actic anhydride. Concentrated HCl (75 ml) was added with care. After the 
addittion of 20 ml of concentrated HCl a very exothermic reaction occurs 
as the acetic anhydride is hydrolyzed. The addition of concentrated HCl 
was done slowly until the acetic anhydride was consumed and the exothermic 
reaction ceased. The reaction composition was reheated to reflux for 2 
hours and stirred overnight or until complete. The reaction was poured 
into 200 ml water and extracted with 200 ml ethyl acetate. The organic 
layer was washed with water and then cautiously with saturated NaHCO.sub.3 
until the water washed were basic. The organic layer was dried 
(MgSO.sub.4) and concentrated to yield a yellow solid. This material was 
recrystallized twice from methanol filtering and the hot solution to 
remove sulfur to give 41 g of (7) (82% yield) (Mp 109.degree.-110.degree. 
C.). 
Synthesis of (8) 
The pyrazolotriazole (7) (40 g, 0.08 mol) was dissolved in tetrahydrofuran 
(200 ml) and treated with acetic anhydride (16 g, 0.16 mol) and pyridine 
(12 g, 0.16 mol) and heated at reflux for 24 hours. The reaction continued 
until complete by thin layer chromatography. The reaction was cooled to 
room temperature (20.degree. C.) and partitioned between ethyl acetate 
(200 ml) and 10% HCl (200 ml). The organic layer was washed with 10% HCl 
(200 ml), dried and concentrated to yield a thick oil which was seeded and 
allowed to stand overnight. The crystalline solid was collected and 
recrystallized from acetonitrile to give a white solid (8) (32 g) (Mp 
65.degree.-66.degree. C.). 
Synthesis of 10 
The nitro intermediate (8) (6 g, 0.0117 mol) was dissolved in 
tetrahydrofuran (50 ml) and treated with 2 g of 10% palladium on carbon 
and shaken with hydrogen overnight (the ease and time required for this 
reaction depends on the sulfur impurity carried from previous steps). The 
reaction was shown to be complete by thin layer chromatography and was 
filtered. The reaction was treated with N,N-dimethylaniline (1.5 g, 0.013 
mol) and a solution of (9) (3 g, 0.013 mol) in 20 ml of tetrahydrofuran 
was added dropwise at room temperature (20.degree. C.) and the reaction 
was stirred for 2 hours. The reaction was partitioned between ethyl 
acetate (200 ml) and 10% HCl (200 ml) and the organic was dried 
(MgSO.sub.4) and concentrated. The residue was recrystallized from 
methanol to yield 5.8 g (10) (74%). 
Synthesis of (11) from (10) 
The pyrazolotriazole (10) (7 g, 0.01 mol) was dissolved in dichloromethane 
and treated with n-chlorosuccinimide (1.6 g, 0.012 mol) at room 
temperature (20.degree. C.) for 3-6 hours. The chlorinated reaction was 
partitioned with H.sub.2 O containing L-ascorbic acid (5 g) and shaken 
well to reduce any excess n-chlorosuccinimide. The organic layer was 
collected and dried (MgSO.sub.4) and concentrated. The residue was taken 
up in 75 ml of tetrahydrofuran and 75 ml of methanol and treated with 2 g 
of 50% sodium hydroxide and stirred at room temperature (20.degree. C.) 
for 2 hours. The reaction was partitioned with ethyl acetate and 10% HCl 
and the organic layer was washed with H.sub.2 O, dried (MgSO.sub.4) and 
concentrated. The solid which was obtained was recrystallized from 
cyclohexane to yield 4.7 g (11) (71%). The product (7) was identified by 
elemental and nmr analysis. 
The couplers of this invention can be incorporated in silver halide 
emulsions and the emulsions can be coated on a support to form a 
photographic element. Alternatively, the couplers can be incorporated in 
photographic elements adjacent the silver halide emulsion where, during 
development, the coupler will be in reactive association with development 
products such as oxidized color developing agent. 
The photographic elements can be either single color or multicolor 
elements. In a multicolor element, the magenta dye-forming coupler is 
usually associated with a green-sensitive emulsion, although they could be 
associated with an unsensitized emulsion or an emulsion sensitized to a 
different region of the spectrum. Multicolor elements contain dye 
image-forming units sensitive to each of the three primary regions of the 
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 art. 
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 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 additional layers, such as filter layers, 
inter-layers, overcoat layers, subbing layers, and the like. 
In the following discussion of suitable materials for use in the elements 
of this invention, reference will be made to Research Disclosure, Dec. 
1978, Item 17643, published by Kenneth Mason Publications, Ltd., The Old 
Harbourmaster's, 8 North Street, Emsworth, Hampshire P010 7DD, ENGLAND, 
the disclosures of which are incorporated herein by reference. This 
publication will be identified hereafter by the term "Research 
Disclosure." 
The silver halide emulsions employed in the elements of this invention 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 silver 
halide grains of any conventional shape or size. Specifically, the 
emulsions can include coarse, medium or fine silver halide grains. High 
aspect ratio tabular grain emulsions are specifically contemplated, such 
as those disclosed by Wilgus et al U.S. Pat. No. 4,434,226, Daubendiek et 
al U.S. Pat. No. 4,414,310, Wey U.S. Pat. No. 4,399,215, Solberg et al 
U.S. Pat. No. 4,433,048, Mignot U.S. Pat. No. 4,386,156, Evans et al U.S. 
Pat. No. 4,504,570, Maskasky U.S. Pat. No. 4,400,463, Wey et al U.S. Pat. 
No. 4,414,306, Maskasky U.S. Pat. Nos. 4,435,501 and 4,643,966 and 
Daubendiek et al U.S. Pat. Nos. 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 GB No. 1,027,146; JA No. 54/48,521; 
U.S. Pat. No. 4,379,837; U.S. Pat. No. 4,444,877; U.S. Pat. No. 4,665,012; 
U.S. Pat. No. 4,686,178; U.S. Pat. No. 4,565,778; U.S. Pat. No. 4,728,602; 
U.S. Pat. No. 4,668,614; U.S Pat. No. 4,636,461; EP No. 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 techniques or by blending 
silver halide emulsions of differing grain 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, i.e., emulsions that form 
latent images primarily on the surfaces of the silver halide grains, or 
internal latent image-forming emulsions, i.e., 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 cyanines and merocyanies), oxonols, hemioxonols, 
styryls, merostyryls, and streptocyanines. 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). 
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-.beta.-(methanesulfonamido)ethylaniline sulfate 
hydrate, 4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline sulfate, 
4-amino-3-.beta.-(methanesulfonamido)ethyl-N,N-diethylaniline 
hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-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 1982, pages 209-211. To 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.

The following examples further illustrate the invention. 
EXAMPLE 1 
(Photographic Elements Comprising Pyrazoloazole Couplers of the Invention) 
Photographic elements were prepared by coating a cellulose acetate-butyrate 
film support with a photosensitive layer containing a silver bromoiodide 
emulsion at 0.91 gm Ag/m.sup.2, gelatin at 3.77 gm/m.sup.2, and one of the 
couplers designated in Table I dispersed in half its weight of tricresyl 
phosphate and coated at 1.62 mmol/m.sup.2. The photosensitive layer was 
overcoated with a layer containing gelatin at 1.08 gm/m.sup.2 and 
bis-vinylsulfonylmethyl ether at 1.75 weight percent based on total 
gelatin. 
Samples of each element were imagewise exposed through a graduated-density 
test object and processed at 40.degree. C. employing the following color 
developing solution, then stopped, bleached, fixed, washed, and dried to 
produce stepped magenta dye images. 
______________________________________ 
K.sub.2 SO.sub.3 2.0 gm 
K.sub.2 CO.sub.3 30.0 gm 
KBr 1.25 gm 
KI 0.6 mg 
4-amino-3-methyl-N- 3.55 gm 
ethyl-N-B'-hydroxy- 
ethylaniline sulfate 
Water to 1.0 liter, pH 10.0 
______________________________________ 
The produced magenta dye images were evaluated as shown in Table I. 
Densitometry of these images provided measures of maximum density 
(D.sub.max) (measure of activity). 
TABLE I 
______________________________________ 
Coupler No. Dmax (measure of activity) 
______________________________________ 
Compound A 1.54 
No. 1 2.70 
No. 2 2.56 
______________________________________ 
Compound A 
##STR10## 
The couplers of the invention provide improved photographic activity. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.