pyridine in acetonitrile

ammonium hydroxide in tetrahydrofuran 1 h; Ambient temperature; Yield given;

hydrogenchloride; sulfur dioxide; copper dichloride; sodium nitrite 1) Acetic acid, formic acid, -8 to -6 deg C, 5 min, 2) room temperature, 15 deg C.; Yield given. Multistep reaction;

Multistep reaction;