Experimental procedure:
EDC·HCl (102 mg, 0.53 mmol) is added in one portion to
1 (200 mg, 0.35 mmol), (
S)-1-phenylethylamine (64 mg, 0.53 mmol) and 2-hydroxy-pyridine
N-oxide (47 mg, 0.42 mmol) dissolved in dichloromethane (2 mL). The resulting solution is stirred at rt for 60 min. More EDC·HCl (50 mg) is added and the mixture is stirred at rt for 15 min more. The solution is washed with a 10% aqueous citric acid solution, water and brine then purified by flash chromatography eluting with 0 to 10% methanol in ethyl acetate. The solvent is evaporated to dryness to afford
2 (185 mg, 98%) as a white solid.