Salsolinol, an Alkaloid Derivative of Dopamine formed in vitro during Alcohol Metabolism

Abstract

THE Pictet–Spengler reaction is a special example of the Mannich reaction involving condensation of β-aryl-ethylamines with carbonyl compounds¹. In the case of phenylethylamines the resulting products would be 1,2,3,4-tetrahydroisoquinolines, which are particularly interesting because they could be formed from endogenous biogenic amines. The synthesis of simple tetra-hydroisoquinolines in physiological conditions which occur in plants was described in 1934². The facility of this chemical reaction between dopamine and acetaldehyde in conditions which exist in both plants³ and animals^4,5 has been confirmed. Because acetaldehyde is the primary metabolite of ethanol, it has been suggested that tetra-hydroisoquinolines are formed in mammals after the ingestion of alcohol^4–6. Indeed, this reaction forms the basis for the histochemical localization of catecholamines in nerve tissue for which formaldehyde vapour is used as the carbonyl agent. Reaction products of this type have been demonstrated in animals after administration of methanol⁷.