Zoanthoxanthins are a collective group of highly fluorescent marine pigments isolated from marine coelenterates which are closely related to sea anemones and stony corals. 1-3 The linear parazoanthoxanthin A (1) and angular pseudozoanthoxanthin A (2) form the basis of this group of tricyclic pigments in which a number of N-methylated derivatives have been identified to date. All contain a bis-fused 2-aminoimidazole (AI) nucleus that embodies a ...