[CH3:1][C:2]1[CH:10]=[CH:9][C:8]([N+:11]([O-:13])=[O:12])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].OS(O)(=O)=O.[CH3:19]O>>[CH3:19][O:5][C:4](=[O:6])[C:3]1[CH:7]=[C:8]([N+:11]([O-:13])=[O:12])[CH:9]=[CH:10][C:2]=1[CH3:1]A solution of 2-methyl-5-nitrobenzoic acid (1.51 g, 8.34 mmol) and H2SO4 (catalytic) in MeOH (20 mL) was heated at reflux for 17 h, then concentrated in vacuo. The residue was dissolved in CH2Cl2 (40 mL), washed with saturated NaHCO3(aq) (30 mL), then dried (MgSO4) and concentrated in vacuo to give yellow crystals (1.62 g, 99%). 1H NMR (CDCl3) δ 2.72 (s, 3H), 3.96 (s, 3H), 7.44 (d, 1H, J=8.7 Hz), 8.24 (dd, 1H, J=8.7, 2.7 Hz), 8.78 (d, 1H, J=2.7 Hz).
Wird geladen…