Securamines

AlkaL indole securamines and securines (seco-securamines) (Securiflustrasecurifrons (Pallas), Bryoz. fitsn North Sea Rahbaek 1997). 

Rahbsek L. Carsten, C. (1997) Three new alkaloids, securamines E-G, from the marine biyozoan Securiflustra securifrons. J. Nat. Prod., 60, 175-7. 

Rahbaek L, Anthoni U, Christophersen C, Nielsen PH, Petersen BO (1996) Marine Alkaloids. 18. Securamines and Securines, Halogenated Indole-Imidazole Alkaloids from the Marine Bryozoan Securiflustra securifrons. J Org Chem 61 887... 

Rahbaek, L., Anthoni, U., Christophersen, C., Nielsen, P. H., and Petersen, B. O., Marine alkaloids. 18. Securamines and securines, halogenatd indole-imidazole alkaloids from the marine bryozoan Securiflustra securifrons, J. Org. Chem., 61, 887, 1996. 

Securamine C from the marine bryozoan Securiflustra Securifrons family has recently been isolated and characterized by researchers at the University of Copenhagen. This interesting hexacyclic structure is an indole-imidazole alkaloid from a family of alkaloids that has yielded important biological activity. This proposal outllines a total synthesis of 1. 

What is left to complete the synthesis of Securamine C is essentiallythe reduction of Cn to a methylene. 

Other approaches. It is also possible to obtain 2-prenylindoles by Pd-catalysed cyclisation of orf/io-alkynylanilines with the prenyl unit situated at the other terminus of the alkyne, as utilised by the Wood group in their work on the total synthesis of the securines and securamines [90]. 

The securines, securamines, chartellines, and chartellamides are members of a structurally unique class of natural products isolated from the bryozoa Chartella papyracea and Securiflustra securifrons by Christophersen and coworkers [65-69] (Fig. 7). Chartellines represent a small family of marine-derived, architecturally unique alkaloids that include chartelline A, chartelline B, and chartelline C, which only differ in the number and position of bromines. Chartelline C (173) is composed of indolenine, imidazole, and jS-lactam heterocycles arrayed in a dense, Ji-stacking framework that poses an obvious challenge for its synthesis [70, 71], Though numerous efforts have been made towards chartelline C (173), rally Baran and coworkers have reported its synthesis [70, 71]. 

Further, in continuation to the synthesis of chartellines, an approach was developed by Baran et al. to construct macrocyclic skeleton and 5-lactam functionality required for chartellines, securamines and securines [73],... 

Scheme 15. Postulated biosynthesis of securines, securamines, chartellines and chartellamides.

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