1: 26 percent / lithium azide / hexamethylphosphoric acid triamide / 18 h / 90 °C 2: 1.) formamide, ammonium sulfate, hexamethyldisilazane, 2.) MeOH / 1.) 120 deg C, 71 h, 2.) reflux, 6 h View Scheme

lithium azide in N,N,N',N',N'',N''-hexamethylphosphoric triamide T=90°C; 18 h;