GB977044A - New compounds and process for preparing them - Google Patents

Abstract

Aryl amino acid compounds useful as colour couplers are prepared by condensing an aryl amino ester, preferably a compound of the formula NH2R-COOR1 (in which R represents a benzene residue which may be substituted with 1 or more carboxy, alkoxy or alkyl groups and R1 is an alkyl group containing 1 to 5 carbon atoms, with a malonic acid di-alkyl ester preferably containing 1 to 3 carbon atoms in the alcohol moiety e.g. dimethyl or diethyl malonate, and subjecting the resulting product to hydrolysis under alkaline conditions. The condensation of the malonic acid dialkyl ester with the aryl amino ester is preferably carried out at a temperature between 150-190 DEG C. and preferably in the presence of a condensation catalyst e.g. a tertiary organic base such as triethanolamine, pyridine, dimethyl aniline or collidine. Specified aryl amino esters are methyl or ethyl p-aminobenzoate, methyl or ethyl m-aminobenzoate, methyl 3-amino iso-phthalate and ethyl 2-methoxy -4- aminobenzoate. The compounds may be used as colour couplers, as such, or in presence of an adsorption means to prevent diffusion such as a long chain fatty acid e.g. lauric or stearic acid. Preferably, however, the compounds are acylated with an acylating agent, for example, either by reaction with a long chain fatty acid halide preferably containing 10-20 carbon atoms e.g. lauroyl or stearoyl chloride preferably in the presence of a tertiary organic base or inorganic base, e.g. sodium or potassium hydroxide or pyridine or dimethyl-aniline or by direct fusion with a long chain substitution derivative of succinic anhydride e.g. hexadecenyl succinic anhydride or octadecenyl succinic anhydride. In an example ethyl-p-amino benzoate is reacted with diethylmalonate in the presence of pyridine and the product substantially treated with aqueous caustic potash to produce. This compound may be treated with lauroyl chloride or octadecynyl succinic anhydride. In another example 3-amino-izo-phthalic acid dimethyl ester is reacted with dimethyl malonate and the product subsequently treated with caustic soda.