Origin of the methyl carbon of methyl coniine in Conium maculatum

Studies with [methyl-¹⁴C]-l-methionine have established that the methyl carbon of l-methionine can act as a precursor of the N-methyl group of methyl coniine in Conium maculatum.     

Alkaloids of Uncaria longiflora

Six isomers of the pentacyclic oxindoie alkaloid mitraphylline and five of their N-oxides have been identified as being present in the leaves of Uncaria longiflora (Poir.) Merr. Isomitraphylline and mitraphylline N-oxides have been prepared and characterized.     

A further quinazoline alkaloid from Adhatoda vasica

A new quinazoline alkaloid isolated from the leaves of Adhatoda vasica has been identified as 1,2,3,9-tetrahydro-5-methoxypyrrolo[2,1-b]quinazoline-3-ol.     

Alkaloids of Stephania sinica

A new hasubanan alkaloid named as runanine was isolated from Stephania sinica. On the basis of spectral analysis, four methoxyl groups could be located at C-2, C-3, C-7 and C-8, respectively. Its structure was determined to be 1. Two other known compounds, cepharanthine and sitosterol, were also obtained from this plant.     

Biosynthesis of papaverine

Tracer experiments have shown that in Papaver somniferum papaverine arises from (−)-norreticuline via norlaudanidine and norlaudanosine.     

Veprisilone,a prenylated 2-quinolone,and limonin from Vepris louisii

A new 2-quinolone alkaloid, veprisilone, isolated from the trunk bark of Vepris louisii has been characterized as 3-(3-hydroxy-3-methyl-2-oxobutyl)- 4,7,8-trimethoxy-1-methyl-2-quinolone from spectral and chemical data. Limonin was also identified in the extracts.     

Parvine,a new angustine-type alkaloid from Nauclea parva

The bark of Nauclea parva contains several alkaloids, the most abundant of which, parvine, is of the corynanthé-type. The proof of structure of this alkaloid is given and its synthesis from harmalan and nicotinoyl chloride is described.     

N-(3-oxobutyl)cytisine: A new lupin alkaloid from eChinosophora koreensis

A new lupin alkaloid, N-(3,-oxobutyl)cytisine, was isolated from the aerial parts of Echinosophora koreensis. Its structure was determined by s