in tetrahydrofuran; dimethyl sulfoxide 1.) -5 deg C, 15 min, 2.) room temp., 3 h;

1: 65 percent / acetonitrile / 4 h / Heating 2: 82 percent / dimethylsulfoxide; tetrahydrofuran / 1.) -5 deg C, 15 min, 2.) room temp., 3 h View Scheme

1: 65 percent / acetonitrile / 4 h / Heating 2: 82 percent / dimethylsulfoxide; tetrahydrofuran / 1.) -5 deg C, 15 min, 2.) room temp., 3 h View Scheme