Verongia cauliformis

MELTING point 193-195°C (dec.) Acetate, 185°C SPECTRAL data UV, IR, PMR, Mass Spec organism Verongia fistularis a.nd Verongia cauliformis (Porifera)... 

Kokke, W.C.M.C., Pak, C.S., Fenical, W, and Djerassi, C. (1979h) Minor and trace sterols in marine invertebrates. XII. Occurrence of 24(R+ S)-isopropenylcholesterol, 24(R -I- S)-25-methyl-cholesta-5,25-dien-3 3-ol, and 24(R-I-S)-methylcholesta-7,25-dien-3p-ol in the Caribbean sponge Verongia cauliformis. Helv. Chim. Acta, 62, 1310-1318. 

The first two members of this series, 2,6-dibromo-4-acetamide-4-hydroxycyclo-hexadienone (1) and the dimethoxyketal 2, were isolated from the methanolic extracts of Verongia fistularis and V. cauliformis by Shanna and Burkholder in 1967 (2-4). Anderson and Faulkner isolated a mixed methoxy-ethoxy ketal 3 from Verongia sp. in 1973. Since the H NMR spectrum of 3 showed two methoxy signals, indicating that 3 is a mixture of two diastereoisomers, 2 and 3 were considered as artifacts generated during the extraction process (5). Faulkner et al. also reported the dienone 4 from Tylodina fungina (6). 

In 1967 Sharma and Burkholder 163) in their continuing search for the antimicrobial activity of sponges succeeded in isolating the first two compounds of the series from the methanolic extracts of Verongia fistularis and V. cauliformis, these were assigned structures (1) and (2). Structure (1) was deduced 164) on the basis of spectral evidence, >.max 257 nm, v ,ax 3445, 1700, 1675 pnd 1660 cm" 6 2.75 (2 H, s), 2.97 (3 H, s) and 7.59 (2 H, s), conversion of its acetate on lithium boro-hydride reduction to the 4-hydroxy-3,5-dibromophenylacetamide (9), and synthesis, which was accomplished by treating (9) in acetic acid with concentrated nitric acid. 

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