Carbon Dioxide → 2,6-Dichloronicotinic acid

Temperature

0 °C

To a solution of diisopropylamine 3.76 g in tetrahydrofuran 25 ml is dropped at −78° C. n-butyllithium (23.2 ml). The mixture is stirred at 0° C. for 10 minutes and thereto is added 2,6-dichloropyridine 5.0 g in tetrahydrofuran 25 ml at −78° C. over a period of 20 minutes. The mixture is stirred at −78° C. for 3 hours. The reaction mixture is poured into powdered dry ice and is left at room temperature overnight. After removal of the solvent the residue is dissolved in a mixture of ethyl acetate and a 10% aqueous sodium hydroxide solution, and the water layer is separated and made acid with concentrated hydrochloric acid. The resulting colorless precipitate is filtered and washed with cold water to give 2,6-dichloronicotinic acid 4.50 g. mp 148–150° C., MS(ESI): 190(M−H)−

1. stirringThe mixture is stirred at −78° C. for 3 hours
2. waitis left at room temperature overnight
3. customAfter removal of the solvent the residue
4. dissolutionis dissolved in a mixture of ethyl acetate
5. customa 10% aqueous sodium hydroxide solution, and the water layer is separated
6. filtrationThe resulting colorless precipitate is filtered
7. washwashed with cold water

ORD record

ord-056d5685a48143628dd28109bd5d52d0

Source dataset

uspto-grants-2007_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07220736B2