1: With di-tert-butyl dicarbonate; 4-(N,N-dimethlyamino)pyridine in tetrahydrofuran T=20°C; 72 h; 2: With lithium aluminium tetrahydride in tetrahydrofuran T=20 - 65°C; 13 h; 3: With Potassium sodium tartrate in tetrahydrofuran; water; ethyl acetate 2 h;