The marine sponge Agelas citrina as a source of the new pyrrole–imidazole alkaloids citrinamines A–D and N-methylagelongine

• Christine Cychon,
• Ellen Lichte and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2029–2037, doi:10.3762/bjoc.11.220

• ) which consist of a pyridinium ring and an ester linkage instead of the aminoimidazole moiety and the common amide bond in PIAs. Keywords: Agelas citrina; marine sponges; mauritiamine; NMR; pyrrole–imidazole alkaloids; Introduction The family of pyrrole-imidazole alkaloids (PIAs) represents a

• using an MTT assay [19]. Selected pyrrole-imidazole alkaloids (1–4, 6–11, and 13–20), and agelongine analogues (5, 12, and 21). Selected 1H,1H-COSY (blue bonds), 1H,1H-NOESY (blue arrows), 1H,13C-HMBC, and 1H,15N-HMBC (both red arrows) correlations for citrinamine A (1). Selected 1H,1H-COSY (blue bonds

• Christine Cychon Ellen Lichte Matthias Kock Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany 10.3762/bjoc.11.220 Abstract The chemical investigation of the Caribbean sponge Agelas citrina revealed four new pyrrole–imidazole

Fe(II)/Et₃N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives

• Ekaterina E. Galenko,
• Olesya A. Tomashenko,
• Alexander F. Khlebnikov,
• Mikhail S. Novikov and
• Taras L. Panikorovskii

Beilstein J. Org. Chem. 2015, 11, 1732–1740, doi:10.3762/bjoc.11.189

• reaction with sulfur affording the corresponding imidazolethiones under very mild conditions. Keywords: imidazole; isoxazole; NHC carbene; pyrrole-2-carboxylate; relay catalysis; Introduction Pyrrole-2-carboxyate and imidazole units are present in bioactive pyrrole-imidazole alkaloids and pyrrole