GB566771A - Improvements in or relating to the formation of coloured photographic images by colour development - Google Patents

Abstract

A colour development coupler for incorporation in a silver halide emulsion or in a developer comprising an aromatic amino developing agent is a compound of formula <FORM:0566771/IV/1> wherein C are carbon atoms in a saturated cyclopentanone or cyclohexanone nucleus and R is a substituted amino group. The coupler may have the formula <FORM:0566771/IV/2> in which n is 2 or 3, in which the benzene nucleus may be replaced by a naphthalene nucleus, and in which R1 may be one or more nitro, alkoxy, carbalkoxy (e.g. carbethoxy), alkyl-substituted amino, or sulphonic (or Na, K, or NH4 sulphonate) groups, or halogen atoms. The ketone ring may contain one or more alkyl substituents except on the carbon atom common to the ring and the chain. The coupler may also have the formula <FORM:0566771/IV/3> wherein n and m may be the same or different and may be equal to 2 or 3. One or both of the terminal rings may contain an alkyl substituent or substituents and both rings may be similarly or dissimilarly substituted, e.g. by alkyl groups. The central benzene nucleus may be replaced by a naphthalene nucleus, and may be substituted as before. The coupler may be added in solution in methyl or ethyl alcohol or ethylene glycol, or a mixture of ethylene glycol and an alcohol. In example 1, a solution in ethylene glycol and methyl alcohol of cyclopentanone-2-carboxylic acid p-nitranilide is added to a colour developer comprising N : N-diethyl-p-phenylenediamine hydrochloride. Example (2) is similar, using the corresponding p-toluidide. Example (3) is similar, using the corresponding p-phenylenedianilide. Cyclopentanone-2-carboxylic acid p-toluidide is prepared by refluxing p-toluidine with ethyl cyclopentanone-2-carboxylate. Cyclopentanone-2-carboxylic acid p-phenylenedianilide is similarly prepared. The p-phenylenediamide of 5-methyl-2-carboxycyclohexanone and 2-cyclopentanone is prepared by first reacting 5-methylcyclohexanone-2-carboxylic acid ethyl ester with p-phenylenediamine and then reacting the product with cyclopentanone-2-carboxylic acid ethyl ester. The p - phenylenediamide of 2 - carboxycyclo - hexanone and 2 - carboxycyclopentanone is similarly prepared. 2-Carboxy-4-methylcyclopentanone anilide is prepared by reacting 4-methylcyclopentanone-2-carboxylic acid ethyl ester with aniline. Cyclohexanone - 2 - carboxylic acid p - toluide is similarly prepared. Cyclopentanone-2 : 4-dicarboxyanilide is prepared by reacting the diethyl ester of cyclopentanone-2 : 4-dicarboxylic acid with two molecular proportions of aniline.