Further terpenoids from the octocorallians cespitularia erecta, xenia viridis and a clavularia SP

• Main Author: Janairo, Jaime Raul O.
• Format: text
• Language: English
• Published: Animo Repository 1995
• Subjects: Corals; Extracts; Terpenes > Spectra; Zoology, Experimental; Chemistry, Organic; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/1208
• Institution: De La Salle University

Spectroscopic investigation of isolates from the liphophilic extracts of three octocorals have added to the rich harvest of terpenoid compounds from these organisms. Cespitularia erecta from the Philippines have afforded the first verticillane-type (geranyl-geraniol cyclized at C2 to C7 and at C3 to C16) diterpene from a marine source. The new compound is keto-functionalized at C12, with the C6 methyl, C6, C7 and C8 further forming a furan ring. Xenia viridis from New Caledonia yielded two related xenicane diterpenoids differing in functionalization at C7 and C8. The more polar compound has an oxirane ring while the second compound is olefinic. Although acetoxy substitution in the xenicanes is common among previously reported compounds, the two compounds are unique in having both C16 and C17 of the prenyl side chain functionalized. The oxirane ring was found to be susceptible to a slow ring opening under the acidic conditions of the n.m.r. experiment resulting in a C6-C7 double bond and conversion of the epoxide to an alcohol at C8. An unknown Philippine Clavularia sp. yielded two more dollabellane diterpenes. The compounds are derivatives of stolonidiol. One is a diacetate with the second acetate on a new oxygenated position on stolonidiol monoacetate, C-2. The other compound is esterified at C-2 with a fatty acid residue.