2-Chloronicotinic acid

Chemical properties

white to cream powder. MP>175°C (decomposition), insoluble in water, soluble in organic solvents such as benzene and toluene.

The Uses of 2-Chloronicotinic acid

2-Chloronicotinic Acid is used in the preparation of 4-thiazolidinone derivatives and Schiff bases displaying antimicrobial activity.

What are the applications of Application

2-Chloronicotinic acid is used in the synthesis of the anti-inflammatory and analgesic pralofen. It is an intermediate of the herbicides nicosulfuron and diflufenican. It is also used as pharmaceutical intermediates for the manufacture of mefenamic acid, niflumic acid, etc.

Preparation

Chloronicotinic acid was synthesized from nicotinic acid by oxidation by H2O2 and then chlorinationby POCl3 and PCl5 in a yield of 87.5%.
Synthesis of 2-chloronicotinic acid: Pour chlorine gas into the mixed solution of phosphorus oxychloride and phosphorus trichloride, control the temperature at about 60°C, until the remaining chlorine gas escapes, cool and add nicotinic acid N-oxide in batches, and heat the mixed solution. The reaction was carried out at 100-105°C for 1-1.5 h, and the reaction mixture was stirred for 30 min after the reaction mixture was transparent, and phosphorus oxychloride was removed under reduced pressure. The obtained residue was cooled to room temperature, and water was added to obtain the finished product of 2-chloronicotinic acid.

Definition

ChEBI: 2-Chloronicotinic acid is an aromatic carboxylic acid and a member of pyridines.

Synthesis

70 g 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 occurred 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 under a vacuum. The residue was allowed to flow into the water at a temperature below 40° C. After adding 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) yielded 65 to 70 percent of the theory.