Pyrrole-imidazole alkaloids

Myer and Kock reported a study of several tetracyclic pyrrole-imidazole alkaloids isolated from marine sponges in 2008 that extensively utilized... 

The pyrrole-imidazole alkaloid taurodispacamide A (486) has been isolated from the Mediterranean sponge Agelas oroides. The structure was established from spectroscopic data. Taurodispacamide A (486) exhibited antihistaminic activity when tested on guinea pig ileum [415]. 

Hoffmann H, Lindel T (2003) Synthesis of the Pyrrole-Imidazole Alkaloids. Synthesis 1753... 

Fattorusso E, Taglialatela-Scafati (2000) Two Novel Pyrrole-Imidazole Alkaloids from the Mediterranean Sponge Agelas oroides. Tetrahedron Lett 41 9917... 

Lindel T, Hochgiirtel M, Assmann M, Kock M (2000) Synthesis of the Marine Natural Product Wa-(4-Bromopyrrolyl-2-carbonyl)-L-homoarginine, a Putative Biogenetic Precursor of the Pyrrole-Imidazole Alkaloids. J Nat Prod 63 1566... 

Grube A, Kock M (2006) Stylissadines A and B The First Tetrameric Pyrrole-Imidazole Alkaloids. Org Lett 8 4675... 

Mourabit AA, Potier P (2001) Sponge s Molecular Diversity Through the Ambivalent Reactivity of 2-Aminoimidazole A Universal Chemical Pathway to the Oroidin-Based Pyrrole-Imidazole Alkaloids and Their Palau amine Congeners. Eur J Org Chem 237... 

Lindel T, Hoffmann H, Hochgiirtel M, Pawlik JR (2000) Structure-Activity Relationship of Inhibition of Fish Feeding by Sponge-Derived and Synthetic Pyrrole-Imidazole Alkaloids. J Chem Ecol 26 1477... 

Pyrrole-imidazole Alkaloids Oroidin -Related Alkaloids... 

Some nonbrominated pyrrole-imidazole alkaloids are included in this chapter, but only when they are close analogs of the corresponding brominated compounds. 

It should be noted that cyclooroidin (38) could be envisaged as the precursor of the nonimidazole bromopyrrole alkaloids longamides (see below). Two cyclooroidin analogs have been isolated agesamide (39) from Agelas sp. [68] and oxocyclostylidol (40) from Stylissa caribica [69]. This latter compound represents the first pyrrole-imidazole alkaloid that includes an oxidized pyrrole moiety. 

The first examples of tetrameric pyrrole imidazole alkaloids, stylissadine A (100) and B, were isolated from the Caribbean sponge Stylissa carihica in 2006 [128]. They possess a symmetric dimeric stmcture derived from condensation of two massadine units, and differ in the configuration at the center C-2. Stylissadines represent the largest pyrrole-imidazole alkaloids isolated so far, and, with their 16 stereogenic centers, they are the most complex stmctures known within the oroidin alkaloid family. 

Assmann et al. described, in addition to known alkaloids, the isolation of the first pyrrole-imidazole alkaloid with a guanidine function instead of the aminoimidazole (127) [152] from the sponge Agdas wiedenmayeri, while its decarboxylated derivate laughine (128) was isolated from the sponge Eurypon laughlini [153],... 

Different molecular mechanisms have been separately postulated for dibromo-phakellin [74], dibromoagelaspongin [91], agelastatin [92], mauritiamine [88], and palau amine [78]. A1 Mourabit and Potier proposed a universal chemical pathway, starting from the simple precursors 101 and 140 and leading to over 60 pyrrole-imidazole alkaloids [80]. A new biomimetic spontaneous conversion of proline to 2-aminoimidazolinone derivatives using a self-catalyzed intramolecular transamination reaction together with peroxide dismutation as key step has been described [166]. This work has pointed to dispacamide A as the forerunner of oroidin and compounds 101 and 140 as probable hydrolysis products of oroidin and not the precursors. In this... 

A brominated pyrrole-imidazole alkaloid, rac-dibromophakellstatin, has been shown to display selective antitumor activity in vitro with the highest activity on the ovarian cancer cell line OVXF 899L <2007BMCL346>. The chemistry and bioactivity of anti-tubulin agents, either natural or synthetic, having an indole as core nucleus have been reviewed <2007MI209>. 

A detailed review on the chemistry of the pyrrole-imidazole alkaloids from marine sponges has been published <03SI753>. 

Marine organisms produce a wide range of alkaloids with potent bio activities, which include such specific classes as 3-aUcylpiperidine, guanidine, indole, polyamine, pyridoacridine, and pyrrole-imidazole alkaloids. Their biological activities vary from antimicrobial to neurological. 

O Malley DP, Li K, Maue M, Zografos AL, Baran PS. Total synthesis of dimeric pyrrole-imidazole alkaloids sceptrin, ageliferin, nagelamide E, oxysceptrin, nakamuric acid, and the axinellamine carbon skeleton. J. Am. Chem. Soc. 2007 129 4762-4775. 

Mourabit AA, Potier P. Sponge s molecular diversity through the ambivalent reactivity of 2-aminoimidazole a universal chemical pathway to the oroidin-based pyrrole-imidazole alkaloids and their palau amine congeners. Fur. J. Org. Chem. 2001 2 237-243. 

The structural revision of marine natural product palau amine and total synthesis of the latter and related pyrrole-imidazole alkaloids 07AG(E)6586. 

C11 H,Br2N50, Mr 387.03). Further examples Oroidin and related heterocycles, the fluorescent parazoan-thoxanthins (see zoanthoxanthins), pilocarpine, the roquefortines C and D., and the topsentins. Some marine pyrrole imidazole alkaloids biosynthetically seem to be the product of combinatorial folding. 

The pyrrole-imidazole alkaloids family comprises hundreds of secondary metabolites originating from marine sponges exclusively. 

Pyrrole-imidazole alkaloids structures can vary with regard to (a) oxidation, reduction or hydration of the 2-amino -4(5)-vinylimidazole unit, (b) dimerization, and (c) cyclization. The... 

Ageladine A (84), from the sponge Agelas nakamurai, is the first isolated pyrrole-imidazole alkaloid containing a 2-aminoimidazolopyridine moiety [78]. 

Figure 12. Other pyrrole-imidazole alkaloids clathramides (78-81), laughines (82-83) ageladine A (84), and latonduines (85-86).

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