A suspension of potassium carbonate (76 mg, 0.55 mmol), and (2-methyl-4-{[4-methyl-2-(4-trifluoromethyl-phenyl)-thiazol-5-ylmethyl]-amino}-phenoxy)-acetic acid methyl ester (225 mg, 0.50 mmol, example 18.2) in DMSO (3 ml) was treated with iodoethane (0.04 ml, 0.53 mmol) in DMSO (0.5 ml) and stirred for 19 h at RT. Again iodoethane (0.34 ml, 4.20 mmol) in 2 portions over 7 h was added. The reaction mixture was taken up in ether and washed with KHSO4-solution (10%). The organic phase was washed with NaCl (10%), dried (Na2SO4) and evaporated. Purification by flash chromatography (SiO2, n-heptane/AcOEt=9/1) gave 141 mg of pure (4-{ethyl-[4-methyl-2-(4-trifluoromethyl-phenyl)-thiazol-5-ylmethyl]-amino}-2-methyl-phenoxy)-acetic acid methyl ester, MS: 479.5 (MH)+.
