Pyrrole-aminoimidazole

Munoz and coworkers [47] isolated and characterized two novel pyrrole— aminoimidazole alkaloids, donnazoies A and B (17 and 18, respectively) from the sponge A. donnai. Data were reported for 17 as the formate salt in d4-methanol and as the triflate salt in dy-DMF, with full assignments from a HMBC spectrum reported for the latter sample. Unfortu-... 

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... 

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],... 

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 chemistry of 2-aminoimidazole derivatives in the synthesis of pyrrole-imidazole alkaoids has been reviewed <2006SL965, 2003S1753, 2001EJ0237>. 

In a study of the synthesis of marine 2-aminoimidazole alkaloids, the aminal C-N bond of bicyclic 898 was cleaved regioselectively to form the allylic amine 899. Deuterium exchange results in H-1, H-2, and H-5, but not H-7 exchange, although the C(6)-C(7) double bond underwent isomerization 901. This is atributed to the assistance of the carbamoyl group that formed the oxazoline 900. Hydrolysis of the carbamate group of 899 under basic conditions affords either pyrrole 902 or pyridine 903 (Scheme 218) <2004OL3933>. 

Vergne, C., Boury-Esnault, N., Perez, T., Martin, M., Adeline, M., Dau, E. T. H., Al-Mourabit, A., (2006). Verpacamides A-D, a sequence of C11N5 diketopiperazines relating cyclo(Pro-Pro) to cyclo(Pro-Arg), from the marine sponge Axinella vaceleti Possible biogenetic precursors of pyrrole-2-aminoimidazole alkaloids. Org. Lett. 8, 2421-2424. 

Pyrrole 2-aminoimidazole alkaloids (PIAs) represent one of the most important groups of sponge secondary metabolites which show a large panel of biological activities [308]. Marine sponges, specifically the Agelasidae and Leucetta families, are the primary sources of structurally diverse secondary metabolites containing a 2-aminoimidazole functionality. Oroidin, isolated in 1971 by Forenza et al., was the first discovered member of this alkaloid family, and since then nearly 150 additional natural products have been isolated [309, 310]. 

Schroif-Gregoire C, Travert N, Zaparucha A, Al-Mourabit A (2006) Direct access to marine pyrrole-2-aminoimidazoles, oroidin, and derivatives, via new acyl-l,2-dihydropyridin intermediates. Org Lett 14 2961-2964... 

Lastly, styhssazoles A-C are new complex pyrrole-2-aminoimidazole alkaloids (P-2-AI) that were isolated from Stylissa carteri collected in the Solomon Islands (Patel et al, 2010). These findings confirm the proposed universal biosynthetic pathway for all currently known dimeric P-2-AI compotmds (Al-Mourabit and Potier, 2001 Kock et al, 2007). 

Patel, K., Laville, R., Martin, M.-T., Tilvi, S., Moriou, C., Gallard, J.-F., Ermolenko, L., Debitus, C., and Al-Mourabit, A. (2010) Unprecedented stylissazoles A-C from Stylissa carteri Another dimension for marine pyrrole-2-aminoimidazole metabolite diversity. Angew. Chem. Int. Ed., 49, 4775-4779. 

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