Process for producing 2,3,5-trichloropyridine
AssigneeCiba-Geigy Corporation
InventorsHansjakob Fah, Alfred Grieder
Life of this patent
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Abstract
Production of 2,3,5-trichloropyridine by reacting 3,5-dichloro-2-pyridone at 30.degree. to 150.degree. with phosgene in the presence of an N,N-disubstituted formamide of the formula ##STR1## in which R.sub.1 and R.sub.2 can be identical or different and are each an alkyl group having 1 to 4 carbon atoms, or R.sub.1 and R.sub.2 together with the nitrogen atom form the pyrrolidino, piperidino or morpholino, and in the presence of an inert solvent. 2,3,5-Trichloropyridine is a valuable intermediate for producing herbicidally active .alpha.-[4-(3',5'-dichloropyrid-2-yloxy)-phenoxy]-alkanecarboxylic acids and derivatives thereof.
Claims10
A process for producing 2,3,5-trichloropyridine which comprises allowing 3,5-dichloro-2-pyridone in an inert organic solvent substantially free of water to react with at least about a molar equivalent amount of phosgene at from about 30.degree. to about 50.degree. C. in the presence of at least about 0.01 molar equivalent amount of an N,N-disubstituted formamide of the formula ##STR3## in which each of R.sub.1 and R.sub.2 is the same or different alkyl group of 1 to 4 carbon atoms or R.sub.1 and R.sub.2 taken together, together with the nitrogen atom to which they are attached, are pyrrolidino, piperidino or morpholino, and neutralizing with base any excess phosgene in the mixture at the completion of the reaction.
Dependencies are inferred from the claim text.