*Review* **Marine Pyrrole Alkaloids**

**Kevin Seipp †, Leander Geske † and Till Opatz \***

> Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany; kseipp@uni-mainz.de (K.S.); legeske@uni-mainz.de (L.G.)

**\*** Correspondence: opatz@uni-mainz.de; Tel.: +49-(0)6131-39-24443

† Both authors contributed equally to this work.

**Abstract:** Nitrogen heterocycles are essential parts of the chemical machinery of life and often reveal intriguing structures. They are not only widespread in terrestrial habitats but can also frequently be found as natural products in the marine environment. This review highlights the important class of marine pyrrole alkaloids, well-known for their diverse biological activities. A broad overview of the marine pyrrole alkaloids with a focus on their isolation, biological activities, chemical synthesis, and derivatization covering the decade from 2010 to 2020 is provided. With relevant structural subclasses categorized, this review shall provide a clear and timely synopsis of this area.

**Keywords:** pyrroles; alkaloids; marine natural products; nitrogen heterocycles; bromopyrroles; pyrrole-imidazole alkaloids; pyrrole-aminoimidazole alkaloids
