To a solution of 2-methoxyacetic acid (41 μl, 0.53 mmol) in CH2Cl2 (1.5 ml), N-cyclohexylcarbodiimide, N′-methyl polystyrene (0.53 g, loading 2 mmol/g, 1.064 mmol), previously washed with CH2Cl2 (5 ml×3), 4-DMAP (0.032 g, 0.266 mmol) and a solution of 2-(4-aminophenyl)-N-(5-isopropyl-1,3-thiazol-2-yl)acetamide (0.076 g, 0.266 mmol) in CH2Cl2/DMF (0.4 ml/10.6 ml) were added. The reaction mixture was maintained under stirring at room temperature for about 72 hours the resin was filtered, washed with CH2Cl2 (10 ml×3), the filtrated combined, washed with water, 5% hydrochloric acid, water, saturated sodium bicarbonate and water, dried and evaporated.
