in tetrahydrofuran; diethyl ether T=0 - 20°C;

4-(N,N-dimethlyamino)pyridine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; triethylamine in DMF (N,N-dimethyl-formamide) T=20°C; 24 h;