in dichloromethane 2 h;

1: NH2OH*HCl, K2CO3 / methanol / 3 h / 60 °C 2: 63 percent / silver carbonate on celite / CHCl3 / 3 h / Ambient temperature; in the dark 3: 56 percent / CH2Cl2 / 2 h View Scheme

1: 63 percent / silver carbonate on celite / CHCl3 / 3 h / Ambient temperature; in the dark 2: 56 percent / CH2Cl2 / 2 h View Scheme