103.1.B (905 mg, 2.65 mmole), 5 ml of DMF and 0.69 ml of DIEA. The reaction mixture was cooled to 0° C., and then ethyl bromoacetate (0.49 g, 2.92 mmole) was added to the mixture. The reaction was stirred at room temperature overnight. After then, the solution was poured into saturated ammonium chloride, and extracted with ethyl acetate. The organic layer was washed with water and brine, and dried over anhydrous sodium sulfate. After concentration in vacuo, the residue was chromatographed on silica gel to give 103.1.C (552 mg, 49% yield) as orange syrup.
