Modern, fast-sweep electrochemical techniques have been applied to the study of the oxidation pathways of catecholamines in vitro. These techniques allow positive identifications of the transient intermediates, i.e., the open-chain o-quinones, and precise determinations of the rate of intramolecular cyclization to the substituted indole and its subsequent oxidation to the aminochrome. Significant differences in the rates of cyclization of adrenaline and noradrenaline are consistent with recent findings on the reactions of these catecholamines.Although the hormonal actions and other functions ax of the catecholamines have been studied extensively, detailed information regarding their reactions at the molecular level is still uncertain. It is well established that the major metabolic pathway of adrenaline and noradrenaline is via O methylation.2•3 However, due to the ease of oxidation of the catechol moiety at physiological pH, oxidative pathways of action cannot be dismissed entirely. Indeed, recent studies in vitro have shown that oxidative reactions of catecholamines are involved in various enzymatic and nonenzymatic processes.4-8 The present study was undertaken to learn more about the chemical reactions which are coupled with oxidative electron transfer in the catecholamines. Experimental SectionMaterials. 1-Adrenaline and adrenochrome were obtained from Sigma Chemical Co., dopamine came from Calbiochem. /-Noradrenaline ¿-bitartrate monohydrate and ¿/-a-methylnoradrenaline hydrochloride were kindly supplied by Dr. S. Archer of Sterling-Winthrop. ¿/-Isoproterenol sulfate dihydrate was that

cephalosporium caerulens, have a unique tricyclic system composed of fused five-, eight-and five-membered rings. The junction between rings A and B and between B and C in ceroplasteric acid and ceroplastol I, however, are both found to be trans, in contrast to the cisltrans disposition in ophiobolins A, B, and C. Furthermore, the absolute configurations at C6, CIO, and Cll are opposite to those found in ophiobolins A, B, and C. In ophiobolin D, the situation is the same as in