Lithium Hydroxide → 4-Amino-2-chloro-3-pyridinecarboxylic acid

Temperatur

85 °C

Methyl 4-amino-2-chloronicotinate (21.0 g, 112.9 mmol) and LiOH (10.3 g, 247.5 mmol) was taken in a mixture of dioxane:MeOH:water (3:2:1, ml) and the reaction mixture was heated to 85° C. for 2 hours. The solvent was evaporated under reduced pressure, the residue was dissolved in minimum volume of water and acidified (up to pH 4) with saturated citric acid. The aqueous solution was concentrated until precipitation just started. The mixture was allowed to stand overnight at 10° C. for complete precipitation. The resultant white solid was collected by filtration and recrystallized from isopropyl alcohol-hexane to afford 4-amino-2-chloronicotinic acid (13 g, 66% yield). 1H NMR (400 MHz, DMSO-d6): δ 7.59 (d, 1H), 6.47 (d, 1H), 6.37 (brs, 2H).

1. customThe solvent was evaporated under reduced pressure
2. dissolutionthe residue was dissolved in minimum volume of water
3. concentrationThe aqueous solution was concentrated until precipitation
4. customto stand overnight at 10° C. for complete precipitation
5. filtrationThe resultant white solid was collected by filtration
6. customrecrystallized from isopropyl alcohol-hexane

ORD-Eintrag

ord-51aede31c2734b40a440721d00614087

Quelldatensatz

uspto-grants-2010_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07829572B2