(1 eq,; typically 25 mg), triethylamine (3 eq.) and HATU (1.3 eq.) and stirred overnight at ambient temperature. The reaction mixture was partitioned between dichloromethane (25 mL) and water (50 mL), and the organic phase was separated. The aqueous component was extracted with further dichloromethane (4 x 10 mL), and the combined organics were then washed with saturated aqueous sodium hydrogen carbonate solution (50 mL) and brine (2 x 50 mL), dried over anhydrous magnesium sulfate and concentrated under reduced pressure.