Patent ID: 6153369
Filing Date: 2000-11-28
Classification: C07D,G03C,Y10S

Abstract:
A photographic element comprising a light-sensitive silver halide emulsion layer having associated therewith a pyrazol-5-one coupler bearing a 4-aryloxy coupling-off group containing a group capable of releasing a photographically useful group (PUG) wherein:(1) the pyrazol-5-one ring contains a 1-aryl substituent which in turn contains, in a position ortho to the bond linking it to the pyrazolone ring, a secondary carbonamido group or a secondary sulfonamido group;(2) the pyrazol-5-one ring contains either (a) a 3-aryl substituent which in turn contains substituents tor which the sum of the Hammett's .sigma. constant values is -0.3 or higher or (b) a 3-alkyl substituent; and(3) the 4-aryloxy coupling-off group:(a) contains ring substituents selected so that the sum of the Hammett's .sigma. constant values for all substituents on the phenoxy ring is at least 0.4 but does not contain a nitro substituent in the ortho position, and:(b) contains in at least one position ortho or para to the oxygen atom bonding the aryloxy group to the pyrazolone ring a substituent 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; andprovided that substituents may join to form one or more additional rings.