The incorporation of (±)-norprotosinomenine,(±)-nororientaline,(±)-nor-reticuline, and (±)- reticuline into boldine in Litsea glutinosa has been studied, and the specific utilization of the (±)-reticuline demonstrated. The evidence supports the direct oxidative coupling of (+)- reticuline to give isoboldine, which in turn is shown to be a specific precursor of boldine. The plants also converted norboldine into boldine. Double labelling experiments involving the ...
