1: With sodium hydroxide in methanol; water T=20 - 45°C; 2: With hydrogenchloride in water pH=2; 3: With phosphorus tribromide in ethyl acetate T=10 - 25°C; 1 h;

phosphorus tribromide in tetrachloromethane

1: L-histidine base With tetraethylammonium hydroxide in water T=10°C; pH=9.2; 2: 1,3-thiazinane-2,6-dione in water T=10°C; pH=8.2 - 9.2; 1 h; 3: With formic acid in water pH=4.2;