p-Toluenesulfonic acid monohydrate → 2-(5-Methoxy-2-hydroxyphenyl)-4-(2-pyridylmethyl)aminomethylbenzoxazole

Participants

Reaction Steps

A mixture of 2-(5-methoxy-2-methoxymethoxyphenyl)-4-(2-pyridylmethyl)aminomethyl-benzoxazole (F16) (283 mg, 0.70 mmol) and p-toluenesulfonic acid monohydrate (532 mg, 2.8 mmol) in methanol (20 mL) was stirred overnight at room temperature. After the solvent was removed by evaporation, ethyl acetate (20 mL) was added to the resulting residue, neutralized by Na2CO3, washed with brine and water, dried over MgSO4, and concentrated in vacuo. The residue was recrystallized from hot ethanol/hexane to afford the objective compound as a pale yellow crystal (244 mg, 96%); 1H-NMR (500 MHz, CDCl3) δ3.86 (s, 3H), 4.01 (s, 2H), 4.21 (s, 2H), 7.05 (br s, 2H), 7.17 (dd, 1H, J=7.5, 4.5 Hz), 7.33-7.37 (m, 2H), 7.41 (d, 1H, J=7.5 Hz), 7.48-7.51 (m, 2H), 7.66 (t, 1H, J=7.5 Hz), 8.59 (d, 1H, J=4.5 Hz), 11.00 (s, 1H).

Provenance & Evidence