Photographic element containing pyrazolone pug releasing coupler and imaging process employing same

Abstract

The invention provides a photographic element comprising a light-sensitive silver halide emulsion layer having associated therewith a 1-aryl-2-pyrazolin-5-one coupler bearing a 4-aryloxy coupling-off group containing a group capable of releasing a photographically useful group (PUG) wherein: (1) the 1-aryl-2-pyrazolin-5-one ring contains a 3-cyano substituent or a substituent linked to the 3-position by an acyl group, thio group, sulfoxide group, sulfone group, or a tetrahedral carbon atom which tetrahedral carbon atom has bonded thereto three other atoms or substituent groups for which the sum of the .sigma.* values is at least 1.5; and (2) the 4-aryloxy coupling-off group: (a) contains ring substituents selected so that the sum of the Hammett's sigma constants for all substituents on the aryloxy ring is at least 0.3 but does not contain a nitro substituent in the position ortho to the oxygen atom bonded to the pyrazolone ring; and (b) contains (i) in at least one position ortho or para to the oxygen atom bonding the aryloxy group to the pyrazolone ring comprising a tetrahedral carbon atom bonded to a PUG or to another timing group which timing group is in turn bonded to a PUG directly or through a further timing group, or (ii) in a position ortho to the oxygen atom bonding the aryloxy group to the pyrazolone ring a carbamate group (with or without a methylene group bridge to the aryloxy ring) bonded to a PUG or to another timing group which timing group is in turn bonded to a PUG directly or through a further timing group; and provided that one or more of the aryloxy ring members or ring substituents may join to form one or more additional rings.

Dependencies are inferred from the claim text.