hydrogen; palladium on activated charcoal in acetic acid 4 h;

1: 62 percent / Et3N / tetrahydrofuran; dimethylformamide / -5 deg C, 1 h, RT, 4 h 2: 68 percent / H2 / 10percent Pd-C / aq. acetic acid / 4 h View Scheme

1: 62 percent / Et3N / tetrahydrofuran; dimethylformamide / -5 deg C, 1 h, RT, 4 h 2: 68 percent / H2 / 10percent Pd-C / aq. acetic acid / 4 h View Scheme

1: 82 percent / conc H2SO4 / acetic acid / 3 h / Heating 2: 62 percent / Et3N / tetrahydrofuran; dimethylformamide / -5 deg C, 1 h, RT, 4 h 3: 68 percent / H2 / 10percent Pd-C / aq. acetic acid / 4 h View Scheme

1: 81 percent / 75percent H2SO4 / 4 h / Ambient temperature 2: 82 percent / conc H2SO4 / acetic acid / 3 h / Heating 3: 62 percent / Et3N / tetrahydrofuran; dimethylformamide / -5 deg C, 1 h, RT, 4 h 4: 68 percent / H2 / 10percent Pd-C / aq. acetic acid / 4 h View Scheme