The main application background and overview of 5-chloro-3-fluoro-2-pyridinecarboxylic acid
5-Chloro-3-fluoro-2-pyridinecarboxylic acid can be used as a pharmaceutical synthesis intermediate. If 5-chloro-3-fluoro-2-pyridinecarboxylic acid is inhaled, move the patient to fresh air; if skin contact occurs, remove contaminated clothing and rinse the skin thoroughly with soap and water. If discomfort occurs, Seek medical attention; if eye contact occurs, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.
Main application preparation of 5-chloro-3-fluoro-2-pyridinecarboxylic acid
The preparation of 5-chloro-3-fluoro-2-pyridinecarboxylic acid is as follows: add 70g ethyl 3-fluoro-5-chloro-2-pyridinecarboxylate (Example P1) to 105ml dimethyl sulfoxide (DMSO) )middle. Add 230ml 2N sodium hydroxide solution dropwise within 30 minutes at 40°C. The resulting yellow suspension was introduced into a mixture of 2 liters of ice water and ml of 2N hydrochloric acid. After stirring for 20 minutes, the mixture was filtered and the filtration residue was washed twice with water. 56.4 g of the desired target compound 5-chloro-3-fluoro-2-pyridinecarboxylic acid were obtained as a white solid. H-NMR (DMSO-d6): 13.79ppm (wide signal, 1H); 8.60ppm (d, 1H); 8.27ppm (dxd, 1H).
Main applications of 5-chloro-3-fluoro-2-pyridinecarboxylic acid
5-Chloro-3-fluoro-2-pyridinecarboxylic acid can be used as a pharmaceutical synthesis intermediate. For example, prepare 3-fluoro-5-chloro-2-pyridinecarbonyl chloride:
Add 71.38g of 5-chloro-3-fluoro-2-pyridinecarboxylic acid into the round bottom flask and heat to 90°C. Within 30 minutes, add 59 ml of thionyl chloride dropwise from the dropping funnel, and introduce the generated gas into the sodium hydroxide solution. It was then stirred at 100° C. for 5 hours, after which thionyl chloride was distilled off at normal pressure. After adding 50 ml of dry toluene, 20 ml of it was distilled off. The resulting solution was poured into 200 ml n-hexane and stirred overnight. After cooling in an ice bath, the mixture was filtered and the filtration residue was washed twice with n-hexane. 68.7 g of the desired compound 3-fluoro-5-chloro-2-pyridinecarboxylic acid chloride were obtained as a brown solid. Cyclohexylamine carbonate H-NMR (CDCl3): 8.60ppm (d, 1H); 7.69ppm (dx methoxypyridine d, 1H).
