Properties of catharanthine

Both catharanthine and vincaleukoblastine in concentrated hydrochloric acid plus a reducing agent (stannous chloride) gave cleavamine (when first isolated the structure of the cleaved  

From the discussion above it becomes easier to understand the problems involved in attempting a synthesis (cf. voacamine, 

The development of the chemistry of the eburnamine alkaloids all from apocynaceous plants was greatly facilitated by the know ledge which had been accumulated on tire canthin-6 ones, bases originally isolated from Pentaceras australis (Rutaceae) and more recently from simarubaceous plants. For this reason a short discussion of their chemistry is in order. 

Canthin-6-ones. From Pentaceras australis, three optically inactive coloured alkaloids were isolated. The structure of canthin-6-one followed from its analytical data, physical properties and potassium permanganate oxidation to j8-carboline-l-carboxylic acid and synthesis from 5-methoxycanthin-6-one vide infra). (Chart 10.2). 

Biogenetic relationships between representative Type III indole alkaloids 

---