Image-dye-forming couplers and photographic elements containing them

摘要

The present invention comprehends the use of thenoylacetamide materials as image-dye-forming couplers, specifically yellow dye-forming couplers, for use with silver halide based photographic systems. In one aspect, the invention provides a coupler of formula (I):- <CHEM> wherein X is H or a coupling-off group, R1 is H or is a coupler-modifying functional group; Y and Z are the same or different and are H or independently selected from alkyl, aryl or heteroaryl, each of which is unsubstituted or substituted with one or more coupler-modifying functional groups; or Y and Z taken together with the nitrogen atom form a 5-10 membered heterocyclic ring which may contain one or more further heteroatoms selected from N, O and S, said heterocyclic ring being unsubstituted or substituted with one or more coupler-modifying functional groups. Preferred couplers are those where Y is H and Z is a phenyl group, which may be mono- or di-substituted.