1.  Field of the Invention
This invention relates to yellow couplers which provide, upon coupling reaction with the oxidation product of a primary amine developing agent, a dye having excellent light fastness (hereinafter merely "fastness" for brevity). 
2.  Development of the Invention
In the field of color light-sensitive materials, it has long been desired to maintain images in their initial state following development state for extended periods of time without change.  Enhancing the light fastness of a dye formed from a coupler is the most basic means to reach this object.  However, unlike cyan couplers and magenta couplers, yellow couplers do not provide a dye having improved light fastness even when they are used together with an anti-fading agents, rather, they provide dyes of deteriorated light fastness.  Therefore, for yellow couplers it has been particularly desired to enhance the light fastness of a dye formed from such a coupler. 
Heretofore, as yellow couplers which provide dyes having good fastness to light those having a pivaloyl group or a derivative thereof as disclosed in U.S. Pat.  No.  3,265,506 have been suggested.  However, these couplers have insufficient fastness and thus it has been desired to synthesize couplers which provide dyes having further improved fastness to light.