Patent GB-765286-A (GB)
Title: Photographic developers
IPC: C07D231/50
Filed: 1955-03-15
Abstract: 765,286. 4-Amino-5-pyrazolone derivatives. AGFA AKT. - GES. FUR PHOTOFABRIKATION. March 15, 1955 [March 15, 1954], No. 7555/55. Class 2 (3). [Also in Group XX] 1 - Phenyl- 4 - amino - 5 - pyrazolone - 3 - carboxylic acid amide is prepared by heating together in an autoclave 1-phenyl-5-pyrazolone- 3-carboxylic acid ethyl ester and ammonia, dissolving the product in water, adding sodium nitrite, and introducing the solution into hydrochloric acid, and reducing the isonitroso compound so obtained with zinc dust and acetic acid. 1 - Phenyl - 4 - amino - 5 - pyrazolone- 3-carboxylic acid ethanolamine is similarly prepared. 1 - Phenyl - 4 - amino - 5 - pyrazolone - 3 - - carboxylic acid methanesulphohydrazide is prepared by adding methanesulphochloride and sodium hydroxide simultaneously to a sodium hydroxide solution of 1-phenyl-5-pyrazolone-3-carboxylic acid hydrazide (prepared by refluxing together 1 - phenyl - 5 - pyrazolone - 3 - carboxylic acid ethyl ester and hydrazine hydrate in ethanol), reacting the product with sodium nitrite and hydrochloric acid to obtain the isonitroso compound, and reducing this with tin sponge and hydrochloric acid. 4 - Amino - 5 - pyrazolone - 3 - carboxylic acid ethyl ester is prepared by heating together sodium acetate, the sodium salt of ethyl oxalacetate and hydrazine sulphate in water, forming the isonitroso derivative by reaction with sodium nitrite and hydrochloric acid, and reducing with tin sponge and hydrochloric acid. 1 - Phenyl - 4 - amino - 5 - pyrazolone - 3 - carboxylic acid hydrazide is prepared by converting 1 - phenyl - 5 - pyrazolone - 3 - carboxylic acid ethyl ester to the isonitroso derivative, reacting with hydrazine hydrate, and reducing with tin sponge and hydrochloric acid. 1 - - p - Sulphophenyl - 4 - amino - 5 - pyrazolone- 3-carboxylic acid ethyl ester is prepared by converting 1 - p - - sulphophenyl - 5 - pyrazolone- 3-carboxylic acid ethyl ester to the isonitroso derivative and reducing with tin sponge and hydrochloric acid. 1-p-Ethoxyphenyl-4-amino- 5-pyrazolone-3-carboxylic acid is similarly prepared. 1 -  p - Aminophenyl - 4 - amino - 5 - pyrazo- Zone-3-carboxylic acid ethyl ester is prepared by converting 1 - p - nitrophenyl - 5 - pyrazolone- 3-carboxylic acid ethyl ester to the isonitroso derivative and reducing with tin sponge and hydrochloric acid. 1 - p - Ethoxyphenyl - 5 - pyrazolone - 3 - carboxylic acid is prepared by reacting together p - ethoxyphenylhydrazine hydrochloride, ethanol, sodium acetate, and the sodium salt of ethyl oxalacetate. 1 - (2 - Tetrahydrothiophenesulphone) - 4- amino - 5 - pyrazolone - 3 - carboxylic acid ethyl ester is prepared by reacting together hydrazine and butadiene sulphone, heating the product with sodium oxalate, ethanol, and glacial acetic acid, and forming the isonitroso derivative and reducing with tin sponge and hydrochloric acid. 1 - Phenyl - 4 - amino - 5 - pyrazolone - 3 - carboxylic acid is prepared by reacting 1-phenyl-5- pyrazolone-3-carboxylic acid with benzenediazonium chloride and reducing the azo dye formed with tin sponge and hydrochloric acid. Specification 459,665, [Group IV], is referred to.