1: N-methylmorpholine, isobutyl chloroformate / 1.) DMF, 20 min, 2.) DMF, RT, 18 h 2: H2 / 5percent Pd/C / methanol / 18 h / 1292.9 Torr 3: 2.) N-methylmorpholine / 1.) methanol, reflux, 1 h, 2.) methanol, 2 h 4: 94.8 percent / 1N HCl, trifluoroacetic acid / 55 °C 5: sodium dithionite / dimethylformamide; H2O / 0.5 h 6: 0.1N NaOH / 1.5 h 7: Me2SO / dimethylformamide / 47 h 8: 0.1N NaOH / acetonitrile View Scheme