The thermally induced rearrangement of 1-substituted imidazoles

Abstract

When passed through a silica tube at 530-600° 1-substituted imidazoles rearrange to form mainly the 2-substituted isomers in high yield. Some ?cracking? occurs with alkyl groups higher than ethyl, while 1- allylimidazole forms about equal quantities of 2- and 4-allylimidazoles. Some study has been made of the reaction mechanism. In sealed silica tubes reaction takes place at lower temperatures but the product complexity increases markedly.