Triethylamine → 2-Chloronicotinic acid

Participants

Reaction Conditions

Reaction Steps

70 gm. of nicotinic acid-N-oxide was suspended in 300 ml of POCl3. Then 50 gm. of triethyl amine was added drop by drop at room temperature, whereby the nicotinic acid-N-oxide dissolved at about 50° C. (the temperature rise occured due to an exothermic reaction). Then the solution was heated in a water bath at 100° C. for another 4 hours. The main quantity of excess phosphorus oxychloride was distilled off under vacuum. The residue was allowed to flow into water at a temperature below 40° C. After addition of diluted caustic soda solution, the 2-chloronicotnic acid precipitated at a pH value of 2.0 to 2.5. The product had a melting point of 173° to 175° C. (Kofler). The product (2-chloronicotinic acid) yield amounted to 65 to 70 percent of theory.

Provenance & Evidence