Methanol → Methyl 5-amino-2-fluorobenzoate
Reaktionsgleichung
[NH2:1][C:2]1[CH:3]=[CH:4][C:5]([F:11])=[C:6]([CH:10]=1)[C:7]([OH:9])=[O:8].S(Cl)(Cl)=O.[CH3:16]O>>[NH2:1][C:2]1[CH:3]=[CH:4][C:5]([F:11])=[C:6]([CH:10]=1)[C:7]([O:9][CH3:16])=[O:8]Komponenten
4
Versuchsvorschrift
To a solution of 5-amino-2-fluorobenzoic acid (89.6 g, 577 mmol) in MeOH (1000 mL) was added sulfurous dichloride (82.4 g, 692 mmol) dropwise at 0° C. Then the mixture was heated to reflux for overnight. The solvent was removed. The residue was diluted with EtOAc (1 L). Then the pH was adjusted to around 9 by progressively adding saturated NaHCO3. The organic layer was separated. The aqueous layer was extracted with EtOAc (500 L×3). The combined organic layers were washed with water and brine successively, dried over Na2SO4, filtered and concentrated under reduced pressure to give the title compound of step A (79.8 g, 81.8% yield). 1H NMR (400 MHz, CDCl3) δ ppm 7.16-7.20 (m, 1H), 6.90-6.98 (m, 1H), 6.75-6.82 (m, 1H), 3.89 (s, 3H), 3.51-3.70 (br, 2H).