反应详情

Dissolve 3′,4′,5′-Trimethoxy-biphenyl-2-carboxylic acid methyl ester (55) (626 mg, 2.08 mmol) in MeOH (14 mL) at rt and add 1M aqu LiOH (4.2 mL, 4.20 mmol). Stir reaction mixture for 8 h under reflux. Remove solvent and partition the residue between 1M aqu. HCl and EtOAc, separate layers, extract the aqu. layer with EtOAc (3×), wash the combined organic layer with brine and dry with Na2SO4. Remove solvent and recrystallize residue from EtOAc/CyH 1+2 to obtain 3′,4′,5′-Trimethoxy-biphenyl-2-carboxylic acid (56) as a white solid (423 mg, 79%). 1H NMR (400 MHz, CD3OD: 3.84 (s, 3H); 3.89 (s, 6H); 6.68 (s, 2H); 7.42-7.49 (m, 2H); 7.57 (t, 1H, J=7.5 Hz); 7.76 (d, 1H, J=8.0 Hz).

1. customreaction mixture for 8 h
2. temperatureunder reflux
3. customRemove solvent and partition the residue between 1M aqu
4. customHCl and EtOAc, separate layers
5. extractionextract the aqu
6. washlayer with EtOAc (3×), wash the combined organic layer with brine
7. dry with materialdry with Na2SO4
8. customRemove solvent and recrystallize residue from EtOAc/CyH 1+2