1: 87 percent / PPh3/H3COCON=NCOOCH3 / tetrahydrofuran / Ambient temperature 2: p-TsOH 4: H2 / Pd-C / ethanol; tetrahydrofuran / 48 h / 2942.03 Torr / Ambient temperature 5: NEt3 View Scheme

1: 84 percent / 4-(dimethylamino)pyridine / CHCl3 / 36 h / Ambient temperature 2: HCl / methanol; CHCl3 / 1 h / Ambient temperature 3: 85 percent / acetonitrile / 6 h / Ambient temperature View Scheme

1: 94.07 g / Et3N / CH2Cl2 / 1.5 h / -5 °C 2: dimethylformamide / 20 h / 90 °C 3: 95 percent / NaOMe / methanol; tetrahydrofuran / 0.5 h / 0 °C 4: 85 percent / BF3*Et2O / CH2Cl2 / 0.75 h / -10 °C 5: Et3N / benzene / 3.5 h / Ambient temperature 6: acetonitrile / 16 h / 50 °C 7: 1.) AgNO3, pyridine, 2.) pyridine, H2S / 1.) MeOH, CH3CN, 0 deg C, 30 min, 2.) CH2Cl2, 0 deg C, 30 min; room temperature, 1 h 8: 15.8 g / DMAP, DCC / CH2Cl2 / 3 h / Ambient temperature View Scheme

1: KOtBu / tetrahydrofuran / 1) r.t., 1 h, 2) reflux, 3 h 2: BF3 / CH2Cl2; methanol / 2 h / 0 °C 4: H2 / Pd/C / ethanol View Scheme

1: 84 percent / 4-(dimethylamino)pyridine / CHCl3 / 36 h / Ambient temperature 2: HCl / methanol; CHCl3 / 1 h / Ambient temperature 3: 85 percent / acetonitrile / 6 h / Ambient temperature 4: 1.) Et3N, 2.) 0.1 M aq. KCl / 1.) CHCl3, r.t., 6 h; 40 deg C, 12 h, 2.) r.t., 1 h 5: 47 percent / CHCl3 / 14 h / 65 °C View Scheme