benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine in dichloromethane T=0 - 20°C; 15 h;

1: in tetrahydrofuran; diethyl ether T=-10°C; 2.5 h; 2: With ammonium chloride in tetrahydrofuran; diethyl ether; water T=20°C; 0.166667 h;