3-(2-carboxymethyl-4-methoxy-6-tolyl)-propionic acid SP:XX
Methanol (GPR)
H₂SO₄

To a solution of the diacid (6.56 g, 26 mmol, 1 equiv) in methanol (200 mL) was added a catalytic amount of conc. H₂SO₄ (0.07 mL, 1.3 mmol, 5 mol%). The mixture was set to reflux for 6 h after which it was allowed to cool to room temperature. The methanol was removed in vacuo and the resulting oil washed with sat. NaHCO₃ solution (20 mL). The organics were extracted into ethyl acetate (3 x 50 mL), dried (MgSO₄), filtered and concentrated in vacuo leaving a brown oil which was seen to be of sufficient purity for use in further reactions. (6.32 g, 87%).

1H nmr (300 MHz, CDCl₃) 6.69 (1H, d, J = 2.5 Hz), 6.66 (1H, d, J = 2.5 Hz), 3.78 (3H, s), 3.72 (3H, s), 3.71 (3H, s), 3.67 (2H, s), 2.94-2.88 (2H, m), 2.45-2.37 (2H, m), 2.34 (3H, s)

Rucker, Mark; Brueckner, Reinhard; Synlett.; 1997; 1187-1189.