Ring contraction of 1,2,4-triazine derivatives in the synthesis of imidazoles

Аннотация

The review systematizes the data on the reactions of 1,2,4-triazines proceeding with a triazine ring contraction to the imidazole one. Imidazole derivatives are obtained upon treatment of 1,2,4-triazines of different saturation degree with reducing agents, oxidants, acids, as well as with the agents initiating tandem reactions, the last step of which is a triazine ring contraction, for example, nitrosating and aminating agents, organometallic compounds and aromatic aldehydes.