Erysodienone Explained

Erysodienone is a key precursor in the biosynthesis of many Erythrina-produced alkaloids.^[1] Early work was done by Derek Barton and co-workers to illustrate the biosynthetic pathways towards erythrina alkaloids.^{[2] [3] [4]} It was demonstrated that erysodienone could be synthesized from simple starting materials by a similar approach as its biosynthetic pathway, which led to the development of the biomimetic synthesis of erysodienone.^[5]

Synthesis

The biosynthesis of erysodienone involves a key step of oxidative phenol coupling. Starting with S-norprotosinomenine precursor A, cyclization via oxidative phenol coupling forms intermediate B, which in turn can be rearranged to form intermediate C. Hydrogenation of C forms the diphenoquinone intermediate E. An intramolecular Michael addition reaction converts E to the final product, erysodienone.^[6]

A biomimetic synthesis route for erysodienone was developed based on a similar oxidative phenol coupling mechanism. Barton and co-workers found that treating bisphenolethylamine precursor F with oxidants such as K3Fe(CN)6 initiated oxidative phenol coupling to form the 9-membered ring structure in intermediate D that itself undergo a Michael addition to give erysodienone.^[7]

Further reading

• Book: Arnold Brossi . Castedo . Luis . Dominguez . Domingo . The Alkaloids: Chemistry and Pharmacology . Chapter 4: Dibenzazonine Alkaloids . January 1989 . Academic Press . 35 . 177–214.
• Chou . Chun Tzer . Swenton . John S. . A convergent strategy for synthesis of Erythrina alkaloids . Journal of the American Chemical Society . October 1987 . 10.1021/ja00256a079 . 0002-7863 . 109 . 22 . 6898–6899.

Notes and References

1. Rahman . Mohammed Zakiur . J Sultana . Shirin . Faruquee . Chowdhury . Ferdous . Faisol . Rahman . Mohammad . S Islam . Mohammad . Rashid . Mohammad A . Phytochemical and Biological investigations of Erythrina variegata . Saudi Pharmaceutical Journal . May 2007 . 15 .
2. Barton . D. H. R. . Boar . R. B. . Widdowson . D. A. . Phenol oxidation and biosynthesis . Part XXI: The biosynthesis of the Erythrina alkaloids . Journal of the Chemical Society C: Organic . January 1970 . 9 . 10.1039/J39700001213 . 0022-4952 . 9 . 1213–1218. 5463829 .
3. Barton . Derek H. R. . Potter . Christopher J. . Widdowson . David A. . Phenol oxidation and biosynthesis . Part XXIII: On the benzyltetrahydroisoquinoline origins of the Erythrina alkaloids . Journal of the Chemical Society, Perkin Transactions 1 . January 1974 . 10.1039/P19740000346 . 1364-5463 . 346–348.
4. Barton . D. H. R. . James . R. . Kirby . G. W. . Turner . D. W. . Widdowson . D. A. . Phenol oxidation and biosynthesis . Part XVIII: The structure and biosynthesis of Erythrina alkaloids . Journal of the Chemical Society C: Organic . January 1968 . 12 . 10.1039/J39680001529 . 0022-4952 . 1529–1537. 5690074 .
5. Book: Herbert . R. B. . The Chemistry and Biology of Isoquinoline Alkaloids . The Biosynthesis of Isoquinoline Alkaloids . 1985 . 213–228 . 0172-6625 . 10.1007/978-3-642-70128-3_14. Proceedings in Life Sciences . 978-3-642-70130-6 .
6. Maier UH . Rödl W . Deus-Neumann B . Zenk MH . Biosynthesis of Erythrina alkaloids in Erythrina crista-galli . Phytochemistry . 1999 . 52 . 3 . 373–82 . 10501023 . 10.1016/s0031-9422(99)00230-7 .
7. Book: M. F. Grundon . The Alkaloids . 1 January 1979 . Royal Society of Chemistry . 978-0-85186-660-4 . 16–.