| 摘要 |
<p>1303679 Halopyridine derivatives IMPERIAL CHEMICAL INDUSTRIES Ltd 22 April 1971 [30 June 1970] 31583/70 Heading C2C 2 - Hydroxy- and 4 - hydroxyhalo - pyridines and salts thereof are prepared by reaction of a halopyridine having a chlorine or fluorine atom in at least one of the 2- and 4-positions with a metal carboxylate in a non-hydroxylic solvent to obtain a salt, followed if desired by hydrolysis and optional resalification. The solvent may additionally contain water. Solvents specified are amides, e.g. dimethyl formamide, dimethyl and diethyl acetamides, N-methyl-pyrrolidone and hexamethyl phosphoramide, ketones, e.g. acetone and cyclohexanane, nitre-compounds, e.g. nitrobenzene and nitromethane, nitriles, e.g. acetonitrile and benzonitrile, pyridine compounds, e.g. pyridine and pyridine N-oxide, sulphoxides, e.g. dimethyl sulphoxide, sulphones, e.g. tetramethylene sulphone, ethers, e.g. diethylene glycol dimethyl ether, alkylene carbonates, e.g. ethylene carbonates, and inorganic anhydrides, e.g. sulphur dioxide. Starting materials specified are fluoro-, chloro- and fluorochloro-pyridines. The products are herbicides. Acid ,fluorides of the acids whose metal carboxylates are used above are also obtained.</p> |
