Reaktion #7105

Reaktionsgleichung

3-bromo-2-fluorobenzoic acid

trimethylorthoformate

p-toluenesulfonic acid

→

methyl 3-bromo-2-fluorobenzoate

Ausbeute 84.0%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturheated
2. 2
   Temperaturunder reflux
3. 3
   Sonstigethe mixture was evaporated
4. 4
   Sonstigethe residue partitioned between water and Et2O
5. 5
   WaschenThe organic layer was washed with sat. sodium hydrogen carbonate solution, water, brine
6. 6
   Trocknendried (MgSO4)
7. 7
   Sonstigeevaporated

Vorschrift

A solution of 3-bromo-2-fluorobenzoic acid (0.219 g, 1 mmol) in dry methanol (5 ml) under nitrogen was treated with trimethylorthoformate (0.22 ml, 2 mmol) and p-toluenesulfonic acid (catalytic amount), and then heated under reflux. After 16 h, the mixture was evaporated and the residue partitioned between water and Et2O. The organic layer was washed with sat. sodium hydrogen carbonate solution, water, brine, dried (MgSO4) and evaporated to give methyl 3-bromo-2-fluorobenzoate (0.195 g, 0.84 mmol, 84%): 1H NMR (CDCl3) δ 7.90–7.85 (m, 1H), 7.71–7.65 (m, 1H), 7.10 (dt, 1H, J=8.0, 1.0 Hz) and 3.94 (s, 3H): MS (EI) 232 (M+).

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