1: With methanol; sodium hydroxide; water in tetrahydrofuran T=75°C; 4 h; 2: With hydrogenchloride in tetrahydrofuran; water pH=1;

1: With sodium hydroxide in water Heating / reflux; 2: With sulfuric acid; sodium nitrite in water T=0 - 4°C; 0.25 h; 3: With hydrogenchloride; tin(ll) chloride in water T=4°C;

1: With sodium nitrite in sulfuric acid T=0°C; 1.25 h; 2: With potassium iodide in sulfuric acid pH=3 - 4; 24 h; Further stages.;

sulfuric acid 6 h; Heating;