(1E)-1-Iodo-3-methyl-1-butene is an intermediate in the synthesis of 4,5-Dehydro-Capsaicin (H951345), an impurity of Capsaicin (C175680) which has been isolated from paprika and cayenne. 4,5-Dehydro-Capsaicin is used as a tool in neurobiological research, and is a prototype vanilloid receptor agonist and topical analgesic.