Process for the synthesis of 2,6-dichloro-5-fluoronicotinic acid and 2,6-dichloro-5-fluoronicotinoyl chloride
AssigneeWarner-Lambert Company
InventorRex A. Jennings
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Abstract
An improved process for the preparation of 2,6-dichloro-5-fluoronicotinoyl chloride is described where a 2,6-dihydroxy-5-fluoronicotinic acid ester is converted in one step using phosphorus oxychloride and a lithium reagent to 2,6-dichloro-5-fluoronicotinoyl chloride and subsequent basic hydrolysis affords 2,6-dichloro-5-fluoronicotinic acid.
Claims27
A process for the preparation of the compound of Formula I ##STR7## which comprises:
- Step (a) heating a compound of Formula III ##STR8## wherein R is lower alkyl or benzyl with POCl.sub.3 in the presence of a lithium reagent and subsequently diluting with a solvent, filtering and distilling to afford the compound of Formula II;
- and ##STR9## Step (b) reacting the compound of Formula II in water with a base, extracting the resulting solution with a solvent, and neutralizing with an acid to afford the compound of Formula I.
A process for the preparation of the compound of Formula II ##STR10## which comprises heating a compound of Formula III ##STR11## wherein R is lower alkyl or benzyl with POCl.sub.3 in the presence of a lithium reagent and subsequently diluting with a solvent, filtering and distilling to afford the compound of Formula II.
Dependencies are inferred from the claim text.