Pseudoceratina verrucosa

The Okinawan sponge Psammaplysilla purea that contains purealidins M-0 (2004-2006) also yields purealidins J (2078), K (2079), L (2080), P (2081), Q (2082), and R (2083) (1835). Purealidin J (2078) is the antipode of pseudocer-atinine A (2089). The Indian sponge Psammaplysilla purpurea, which is the source of purpurealidins F-H (2018-2020) and other bromotyrosines (vide supra), also contains purpurealidins A (2084), B (2085), C (2086), and D (2087) (1842). A Caribbean Pseudoceratina sponge has afforded the simple carboxylic acid 2088 (1868). The New Caledonian sponge Pseudoceratina verrucosa, which is the source of pseudoceratinine B (1990), also contains pseudo-ceratinines A (2089) and C (2090), the absolute configurations of which are shown (1829). 

Benharref A, Pais M, Debitus C (1996) Bromotyrosine Alkaloids from the Sponge Pseudoceratina verrucosa. J Nat Prod 59 177... 

The enantiomer of purealidin J, pseudoceratinine A (119), was reported one year later from Pseudoceratina verrucosa 89). Pseudoceratinine A showed a negative optical rotation and Cotton effects near 250 and 290 nm, which is opposite to that of aerothionin (68), whose absolute stereochemistry was determined by X-ray and CD spectra 60). Aplysinamisine I (120), which can be considered as a 11,12-dehydro product of aerophobin-2 (114), was isolated from the Caribbean sponge Aplysina cauliformis 83). 

Pseudoceratinine B (151), in which the oxime is reduced and tri-methylated, was isolated from Pseudoceratina verrucosa (89). The absolute configuration of tyrosine was deduced from the positive Cotton effect at 212 nm, corresponding to an 5-configuration (106). Pseudoceratinine B (151) is the second bromotyrosine alkaloid containing a non-oxidized amino group. 

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