Alkaloid biosynthesis. Part XI. Studies related to the formation and oxidation of reticuline in morphine biosynthesis

Abstract

Several routes which had earlier been considered as possible ones for the biosynthesis of morphine alkaloids are excluded by appropriate tracer studies. Thus, (+)- and (–)-codamine, (±)-reticuline methochloride (= tembetarine chloride) and bis-3,4-dihydroxyphenethylamine (XXIV) are synthesised and shown not to act as precursors of morphine. Multiple labelling experiments are carried out to examine details of oxidation–reduction processes over that part of the pathway between norlaudanosoline (I) and reticuline (IV).

The preparation of (+)- and (–)-OO-diethylreticuline and the incorporation of norlaudanosoline into papaverine are described.