Studies on the biosynthesis of the morphine alkaloids

2018-07-26T09:02:47Z (GMT) by Stewart R. Massey
Earlier work on the biosynthesis of morphine in the opium poppy, Papaver somniferum, is reviewed in chapter I. A variety of unnatural codeine precursors, closely related structurally to codeine and labelled with 3H at C-2, have been prepared and administered to P. somniferum plants. Their in vivo 3-0-demethylation to give the corresponding morphine compounds was investigated using radiodilution techniques. Each of the feeding experiments utilised [N-methyl-14C]codeine as an internal standard and the efficiency of the unnatural 3-0-demethylations was compared with that observed for the natural conversion of codeine into morphine. Dihydrodesoxycodeine was more efficiently converted into dihydrodesoxymorphine than was codeine into morphine. The least efficiently demethylated unnatural precursor of the series was 1-bromocodeine. [Continues.]