A mixture of methyl 4-(N-cyclopentylamino)-3-iodobenzoate from above (22.42 g, 65 mmol), palladium acetate (738 mg, 3.28 mmol), lithium chloride (2.757 g, 65 mmol), potassium acetate (12.757 g, 92.30 mmol), and 1-trimethylsilyl-1-propyne (28.70 mL, 192.56 mmol) in 390 mL of DMF was heated at 100° C. for 6 hours. The mixture was added onto 500 mL of saturated aqueous ammonium chloride solution and extracted with ethyl acetate. The ethyl acetate fraction was dried, evaporated and semi-purified by flash chromatography using silica gel and 0.1% ethyl acetate in hexane. Adding hexane to the semi-purified compound gave 16 g of white crystals (75%).
