| abstract |
This invention relates to an imaging element comprising an imaging layer having associated therewith a compound of Structure I:wherein PUG is a residue of removing a hydrogen fromwherein X, Y, and Z represent substituents selected independently from the groups hydrogen, alkyl group of 1 to 6 carbon atoms, cyclopropyl, aryl, arylalkyl, and heterocyclic groups, wherein at least one of X, Y, and Z is an aryl group and one of X, Y, Z, which may or may not be an aryl group, is attached in the direction of the backbone, and the other substituents are as defined in the specification. Such compounds have good reactivity and can by used to block photographically useful compounds such as developing agents until thermally activated under preselected conditions. Compounds according to the present invention are especially useful in color photothermographic imaging elements. |