Patent GB-385214-A (GB)
Title: Process for the manufacture of readily soluble derivatives of the pyridine series
IPC: C07D213/69
Filed: 1932-06-10
Abstract: Salts of aliphatic amines with hydroxy- or oxo-bromo- or iodo-pyridines containing salt-forming acidic groups are prepared by interaction of their components.  Being readily water-soluble, they are useful as contrast media in X-ray photography.  Examples are given of the preparation of salts of (1) 3 : 5-diiodo-4-pyridone-N-acetic acid with diethylamine, bis-hydroxyethylamine, 2-oxo-3-methyl-4-dimethylaminobutane, 1 - ethoxy - 2 - hydroxy - 3 - dimethylaminopropane, 2 - hydroxy - 4 - diethylaminobutane, 1 : 3 - bis - diethylamino-2 - hydroxypropane, bis - hydroxyethylaminoethane, 1 - hydroxyethoxy - 2 - diethylaminoethane, 1 - diethylaminoethoxy - 2 - hydroxy-3 - dimethylaminopropane, diethylaminoethyl-hydroxyethyl - thioether (see Specification 286,087, [Class 2 (iii), Dyes &c.]), and diethylaminoacetic acid ethylester; (2) 3 : 5-diiodo-2-pyridone - N - acetic acid and diethylamine; (3) 5-iodo-2-pyridone-N-acetic acid with diethylamine and 1 - ethoxy - 2 - hydroxy - 3 - dimethylaminopropane; (4) 3 : 5-diiodochelidamic acid and its N-methyl derivative, 3 : 5-diiodo-4-pyridone-N-ethanesulphonic acid, and 3 : 5-dibromo-4-pyridone-N-acetic acid with diethylamine.  A comparison is made between the solubility of the products with that of the corresponding sodium salts.  Aliphatic amines.--2 - Oxo - 3 - methyl - 4 - dimethyl (or diethyl) aminobutane is prepared by condensing methylethylketone, formaldehyde and dimethyl- or diethyl-amine. 1-Ethoxy-2-hydroxy-3-dimethyl (or diethyl) aminopropane is produced by converting epichlorhydrin by means of dimethyl- or diethyl-amine into 1 - chloro - 2 - hydroxy - 3 - dimethyl (or diethyl) aminopropane, which is then treated with sodium ethylate. 2-Hydroxy-4-diethylaminobutane results from the condensation of acetone, formaldehyde and diethylamine, followed by reduction. The interaction of chloro-alcohol with diethylamino-sodium ethylate yields 1 - hydroxyethoxy - 2 - diethylaminoethane.  1 - Diethylaminoethoxy - 2 - hydroxy - 3 - dimethylaminopropane is prepared by acting on 1 - chloro - 2 - hydroxy - 3 - dimethylaminopropane with diethylamino-sodium ethylate.ALSO:Salts of aliphatic amines with hydroxy- or oxobromo- or iodo-pyridines containing saltforming acidic groups, being readily watersoluble, are useful as contrast media in X-ray photography of internal organs of the body.  The following salts are specified:-3 : 5-diiodo-4-pyridone-N-acetic acid with diethylamine, bis-hydroxyethylamine, 2-oxo-3-methyl-4-dimethylaminobutane, 1-ethoxy-2-hydroxy-3-dimethylaminopropane, 2 - hydroxy - 4 - diethyl - aminobutane, 1 : 3-bis-diethylamino-2-hydroxypropane, bis-hydroxyethylaminoethane, 1-hydroxyethoxy-2-diethylaminoethane, 1-diethylaminoethoxy - 2 - hydroxy - 3 - dimethylaminopropane, diethylaminoethyl-hydroxyethyl-thioether and diethylaminoacetic acid ethylester; 3 : 5-diiodo-2-pyridone-N-acetic acid and diethylamine; 5-iodo-2-pyridone-N-acetic acid with diethylamine and 1-ethoxy-2-hydroxy-3-dimethylaminopropane, 3 : 5-diiodochelidamic acid and its N-methyl derivative, 3 : 5-diiodo-4-pyridone-N-ethanesulphonic acid and 3 : 5-dibromo-4-pyridone-N-acetic acid with diethylamine.  A comparison is made between the solubility of the products with that of the corresponding sodium salts.