Pyrrole-Imidazole Alkaloids from Marine Sponges: Structural Variation and Cytotoxicity of (¿)-Dibromophakellstatin, Synthesis of Ugibohlin and Oroidin, and Studies Towards Oxocyclostylidol

Bücher

Angebote / Angebote:

Oroidin is considered to be the biogenetic key metabolite of the pyrroleimidazole alkaloids. Several syntheses are known to date, all of which contain steps with only moderate yields. For a study on its reactivity large quantities are needed. Therefore, an improved synthesis would be beneficial. In the present work two different known routes to 8 were investigated. By following the method developed in our group (via Sonogashira coupling) several analogues arose as new products. By treating the two deaminated analogs 1 and 4 with NBS in TFA, no cyclization to the phakellin skeleton 3 took place. Instead, pyrrole oxidation occurred (Scheme 1).