A mixture of methyl trans-4-chloro-2-(phenylsulfonylamino)cinnamate (step 1 of Example 8, Method A, 700 mg, 1.99 mmol), 2-bromoacetyl-4-ethylpyridine* (545 mg, 2.39 mmol), potassium carbonate (1.37 g, 13.9 mmol) and acetone (20 ml) was stirred at room temperature. After stirring for 3 h, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 0.6 ml, 3.98 mmol) was added. The resulting mixture was stirred for an additional 19 h and then concentrated. The residue was diluted with dichloromethane (200 ml) and washed with water (100 ml×2). The organic layer was dried (MgSO4) and concentrated. The residue was purified by flash column chromatography eluting with ethyl acetate/hexane/dichloromethane (1:4:1) to give the title compound including impurity. The crude product was washed with ethyl acetate to give 297 mg (42%) of the title compound as yellow solids.
