Two diterpenes, epipolone (1) and epipolol (3), produced by terpenoid pathways leading to a tricarbocyclic structure with an irregular "head to tail" isoprene configuration, have been isolated from the Caribbean marine sponge Epipolasis reiswigi collected in Puerto Rico. The structures of 1 and 3 were elucidated largely by 1D and 2D NMR methods and chemical conversion.
Three new cyclic peptides, euryjanicins B (2), C (3), and D (4), have been isolated from the Puerto Rican marine sponge Prosuberites laughlini, and the structures were elucidated by chemical degradation, ESIMS/MS, and extensive 2D NMR methods. When tested against the National Cancer Institute 60 tumor cell line panel, all of the purified isolates displayed weak cytotoxicity.
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Abstract Three new cembrane‐based diterpenes possessing the rare 3,14‐oxa‐bridged moiety were isolated from the hexane extract of a southwestern Caribbean gorgonian octocoral, Eunicea pinta , together with seven known cembranoid diterpenes. The structures of pintoxolanes A–C ( 1 – 3 , resp.), including their relative configurations, were deduced from spectroscopic data and chemical‐correlation experiments. Experimental evidence hinting to a plausible biogenesis of the 3,14‐oxalane moiety is provided. Preliminary cytotoxicity data for compounds 1 – 3 toward human cancer cell lines are also provided.
Two new five-membered-ring polyketide endoperoxides, epiplakinic acid F methyl ester (1) and epiplakinidioic acid (3), and a peroxide-lactone, plakortolide J (2), were isolated from the Puerto Rican sponge Plakortis halichondrioides, along with two previously reported cyclic peroxides, 4 and 5. The structures of the new metabolites were determined by spectroscopic and chemical analyses. The absolute stereostructures of 1, 2, and 5 were determined by degradation reactions followed by application of Kishi's method for the assignment of absolute configuration of alcohols. Biological screening of cycloperoxides 1−5 and semisynthetic analogues 7−12 for cytotoxic activity against various human tumor cell lines revealed that compounds 3, 4, and 11 are very active. Upon assaying for antimalarial and antitubercular activity, some of the compounds tested showed strong activity against the pathogenic microbes Plasmodium falciparum and Mycobacterium tuberculosis.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract isolation, structure determination and preliminary cytotoxicity data of three new cembrane‐based diterpenes, pintoxolanes A (I), B (IIa) and C (IIb)
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