Colour couplers and their production and use in colour photography

The invention comprises colour couplers of the formula: where A is the trivalent radical: D is a direct linkage or the divalent radical: in which X is -S- or -CONH-, R is a hydrocarbon group and B is a colour coupler residue such that the compound: is a compound which will react with the oxidation products of N, N-diethyl para-phenylene diamine, formed during the development of a silver salt image with that compound, to yield a quinoneimine or azomethine dyestuff. The above compounds are prepared by heating a compound of the formula: with a compound of the formula: B-CO-halogen or B-COOM, wherein M represents C1-6 alkyl or phenyl. Compounds of the formula B-CO-halogen or B-COOM are, for example: (1) Those in which B contains a mono- or bicyclic aryl radical, e.g. ethyl benzoylacetate, ethyl 4-methoxybenzoylacetate, ethyl 2-methoxy-benzoylacetate, ethyl 4-N-dimethylaminobenzoyl-acetate and ethyl (2-methyl-2, 3-dihydrobenzofuran -7- ylcarbonyl) - acetate. (2) Those which contain a pyrazolane ring, e.g. 1 - (4-carbethoxyphenyl) -3- acetylamino -5-pyrazolone, 1-phenyl -3- carbethoxy -5- pyrazolone and 1-phenyl -3- (2-carbphenoxybenzoylamino) -5- pyrazolone. (3) Those which contain a phenol or 1-naphthol residue, e.g. phenyl salicylate, phenyl 1-hydroxy -2- naphthoate and phenyl 1-hydroxy-4-chloro-2-naphthoate. It is stated that the addition of the above colour couplers to dilute alkali (e.g. potassium or sodium hydroxide) has the effect of opening the ring structure: to provide a free carboxylic group after neutralization with, e.g. acetic acid. 4 - Amino - N - n - dodecylphthalimide, 4 - amino - N - n - octadecylphthalimide 4 - aminophenylsuccin - N - (4 - n - dodecylphenyl) - imide, 4 - amino - N - (4-n-dodecylphenyl)-phthalimide, 4 - (4 - aminobenzoylamino) - N - n - octadecylphthalimide and 4 - aminophenylthiosuccin - N -(4 - n - dodecylphenyl) - imide are prepared by reduction of the corresponding nitro compounds. 4 - Nitro - N - n - dodecylphthalimide and 4 -nitro - N - n - octadecylphthalimide are prepared by reacting 4-nitrophthalic anhydride with n-dodecylamine and n-octadecylamine respectively. 4 - Nitrophenylsuccin - N - (4 - n - dodecylphenyl) - imide, 4 - amino - N - (4 - n - dodecylphenyl) - phthalimide and 4 - nitrophenylthiosuccin - N - (4 - n - dodecylphenyl) - imide are prepared by reacting 4-n-dodecylaniline with 4-nitro-ph