phosphorus tribromide in di-isopropyl ether T=0 - 35°C; 1 h;

hydrogen bromide in acetic acid T=50°C; 2 h;

acetone; sodium bromide

in ethanol; water 5 h; Heating / reflux;

1: 2,4-dimethylbenzyl bromide; Ni(II) complex of the Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone With sodium hydroxide in N,N-dimethyl-formamide T=20°C; 2: With hydrogenchloride in methanol T=70°C; 3: di-tert-butyl dicarbonate With sodium carbonate in 1,4-dioxane; water T=20°C;