Imidazole derivatives which are useful intermediates for the production of compounds having pharmacological activity at histamine H.sub.2 receptors. A specific compound of the present invention is 4-(4-aminobutyl)-1,3-dihydro-5-methyl-2H-imidazole-2-thione, hereinafter referred to as 4-(4-Aminobutyl)-5-methylimidazole-2-thione.