Imaging element containing a blocked photographically useful compound

摘要

This invention relates to an imaging element comprising an imaging layer having associated therewith a compound of Structure I: In the above Structure I, the substituents are as defined in the application, wherein B is a six-membered heteroaromatic ring. 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.