Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
1998-12-30
2001-08-28
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S544000, C430S955000, C430S956000, C430S957000, C430S950000, C430S959000, C430S960000
Reexamination Certificate
active
06280919
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a photographic element having a light-sensitive silver halide emulsion layer having associated therewith a stable 1-aryl-3-arylpyrazol-5-one based magenta coupler having an aryloxy group linked by its oxygen atom to the 4-position of the pyrazolone ring.
BACKGROUND OF THE INVENTION
In a silver halide photographic element, a color image is formed when the material is exposed to light and then developed using a primary amine color developer. The development results in imagewise reduction of silver halide and the corresponding production of oxidized developer. The oxidized developer then reacts in an imagewise fashion with one or more incorporated dye-forming couplers to form a dye image.
Magenta dye-forming couplers are employed in subtractive color forming processes. One of the principal coupler types useful for this purpose are those based on a pyrazolone ring. Pyrazolone-based couplers having a coupling-off group linked to the pyrazolone ring by oxygen have long been considered as potentially attractive two equivalent magenta couplers. An oxygen-linked coupling-off group could impart increased activity to the pyrazolone coupler; however the general instability of these couplers toward ambient oxygen makes them difficult to synthesize and impractical for use in a film environment since they decompose during keeping. In particular, pyrazolone couplers having an anilino or acylamino substituent at the 3-position have exhibited unacceptable stability when an aryloxy is employed as a coupling-off group. As a result, pyrazolone couplers have employed either so-called “four equivalent” couplers containing hydrogen at the coupling-off position or have employed so-called “two-equivalent” couplers containing a coupling-off group having a sulfur or nitrogen atom linked to the pyrazolone ring.
U.S. Pat. No. 3,419,391 discloses certain types of pyrazolone-based compounds as two-equivalent couplers having high dye-forming reactivity and reduced tendency to form color fog. According to the patent, the pyrazolone ring is not limited to the presence of any particular substituents at the 3-position or elsewhere. Specifically identified substituents at the 3-position include anilino, acylamino, alkyl, amino, alkoxy, amido, carbamoyl, ureido, thio, guanidino, etc. The couplers of the patent may contain an aryl group at the 1-position and, among other things, an alkyl or carboxy ester group at the 3-position. The aryloxy couplers of the patent are said not to produce color fog (printout) and to provide improved reactivity. Thus, they arc said to provide low printout or yellowing in Dmin areas when they are exposed to light or high temperatures, respectively, subsequent to development. No mention is made of the poor keeping of pyrazolone couplers having aryloxy coupling-off groups although their instability is well known in the art.
U.S. Pat. No. 5,576,167 describes a family of two-equivalent pyrazolone couplers with good stability towards oxygen. The features that make these compounds stable are: (a) an electron-withdrawing CXYZ substituent in the 3-position of the pyrazolone ring, and (b) an aryloxy group, further substituted by electron-withdrawing group(s) in the 4-position of the ring. Although stable, the couplers of this patent require a multistep procedure for their preparation and some of these steps are difficult to perform. None of these references discloses magenta couplers of this invention.
It would therefore be desirable to have a pyrazolone-based coupler with an aryloxy coupling-off group present in a photographic element that is stable during synthesis, film manufacture, and during film keeping and would provide an acceptable hue and reactivity but which would not be difficult to prepare. The 1-aryl-3-arylpyrazolo-5-one magenta dye forming couplers of this invention provide these and other desirable advantages.
SUMMARY OF THE INVENTION
The invention provides a photographic element comprising a light-sensitive silver halide emulsion layer having associated therewith a coupler based on a 1-aryl-3-arylpyrazol-5-one ring and represented by formula I:
wherein:
Z represents hydrogen, alkyl, aryl, halogen or a group further defined as:
wherein:
X represents an aryl, alkyl, alkylamino, or an arylamino group;
Y represents carbon or sulfur; m is 1 when Y is carbon and 2 when Y is sulfur;
($) denotes the bond connecting the nitrogen atom and the phenyl ring;
R represents a halogen, an alkyl group, an alkoxy group, a cyano group, and a nitro group; and o is 0 to 4; and provided further that R may not be a nitro group ortho to the bond linking the phenyl ring to the 1 position of the pyrazolone ring; and
Ar
3
represents an aryl group;
Q represents n independently selected substituents bonded to the Ar
3
ring, provided that the sum of the appropriate Hammett's &sgr; constants for all Q substituents is at least 0.05; and n is 1 to 5, provided that two or more Q substituents may join to form one or more additional rings;
OAr
4
is an aryloxy group;
P represents p independently selected substituents bonded to the aryloxy ring, provided that the sum of the appropriate Hammett's &sgr; constants for all P substituents is at least 0.4, and provided further that P may not be a nitro group ortho to the oxygen atom linking the aryloxy group to the 4 position of the pyrazolone ring, provided that two or more P substituents may join to form one or more additional rings, and p is 1 to 5.
The invention also encompasses a process for forming an image in the described element after exposure to light comprising contacting the clement with a color developing chemical.
A photographic element in accordance with the invention exhibits an improved keeping stability of the magenta dye forming coupler and acceptable hue and reactivity even in the absence of a stabilizing, compound.
REFERENCES:
patent: 3419391 (1968-12-01), Young
patent: 4686175 (1987-08-01), Ogawa et al.
patent: 4985336 (1991-01-01), Ichijima et al.
patent: 5576167 (1996-11-01), Poslusny et al.
patent: 5670306 (1997-09-01), Poslusny et al.
Poslusny Jerrold N.
Slusarek Wojciech K.
Wu Zheng Z.
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
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