Three diterpenes from the red alga Sphaerococcus coronopifolius

Cafieri, Francesco; Ciminiello, Patrizia; Santacroce, Ciro; Fattorusso, Ernesto

doi:10.1016/s0031-9422(00)80282-4

Cited by 25 publications

(27 citation statements)

References 6 publications

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“…Accordingly, we herein investigated the ruthenium-complex-catalyzed CM of methallyl halides with several functionalized olefins and its application to the formal total synthesis of a sphaeroane diterpene, (–)-presphaerene ( 1 ) ( Figure 2 ) (Cafieri et al, 1983 ).…”

Section: Introductionmentioning

confidence: 99%

Cross-Metathesis of Methallyl Halides: Concise Enantioselective Formal Total Synthesis of (–)-Presphaerene

et al. 2020

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The cross-metathesis (CM) of methallyl halides catalyzed using four different ruthenium-based complexes-Grubbs catalyst, Grubbs second-generation catalyst, Hoveyda-Grubbs second-generation catalyst, and Stewart-Grubbs catalyst-was investigated. When methallyl chloride or bromide was reacted with a model substrate containing a benzyl ether group, the Grubbs catalyst, and Grubbs second-generation catalyst did not promote the reaction well. However, the Hoveyda-Grubbs second-generation catalyst and Stewart-Grubbs catalyst afforded the corresponding products in moderate to good yield with moderate E/Z selectivity. Accordingly, several functionalized methallyl halides were prepared by CM. Various functional groups were well-tolerated in this system when the Stewart-Grubbs catalyst was used. To demonstrate the practical utility of our method, methallyl halide CM was successfully employed for the formal total synthesis of a natural product (-)presphaerene, in which the precursor of the key cyclopentanecarboxylate intermediate was efficiently prepared in three steps.

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Section: Introductionmentioning

confidence: 99%

Cross-Metathesis of Methallyl Halides: Concise Enantioselective Formal Total Synthesis of (–)-Presphaerene

et al. 2020

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“…Since its first chemical analysis in 1976, the cosmopolitan red alga, Sphaerococcus coronopifolius , has yielded a large number of interesting brominated cyclic diterpenes, most of them containing one or two bromine atoms [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Concerning the biological activities of these compounds, some of them have already demonstrated antibacterial activity against Gram-positive bacteria [ 33 ], and others have been assayed for their cytotoxicity against human lung cancer cell lines [ 37 ] or their antibacterial activity against multidrug-resistant and methicillin-resistant Staphylococcus aureus strains [ 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Antitumor and Antimicrobial Potential of Bromoditerpenes Isolated from the Red Alga, Sphaerococcus coronopifolius

et al. 2015

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Cancer and infectious diseases continue to be a major public health problem, and new drugs are necessary. As marine organisms are well known to provide a wide range of original compounds, the aim of this study was to investigate the bioactivity of the main constituents of the cosmopolitan red alga, Sphaerococcus coronopifolius. The structure of several bromoditerpenes was determined by extensive spectroscopic analysis and comparison with literature data. Five molecules were isolated and characterized which include a new brominated diterpene belonging to the rare dactylomelane family and named sphaerodactylomelol (1), along with four already known sphaerane bromoditerpenes (2–5). Antitumor activity was assessed by cytotoxicity and anti-proliferative assays on an in vitro model of human hepatocellular carcinoma (HepG-2 cells). Antimicrobial activity was evaluated against four pathogenic microorganisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Compound 4 exhibited the highest antimicrobial activity against S. aureus (IC50 6.35 µM) and compound 5 the highest anti-proliferative activity on HepG-2 cells (IC50 42.9 µM). The new diterpene, sphaerodactylomelol (1), induced inhibition of cell proliferation (IC50 280 µM) and cytotoxicity (IC50 720 µM) on HepG-2 cells and showed antimicrobial activity against S. aureus (IC50 96.3 µM).

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“…[3] Secondary metabolites derived from marine organisms, often featuring previously unknown skeletons, provide a broad range of biological activities. [6][7][8][9][10][11][12][13][14][15] As part of our ongoing interest in the natural products chemistry of marine organisms of the Greek seas and their potential utilization in the development of new antifouling, antibacterial and anticancer agents, we have previously reported a number of new bioactive diterpenes, some possessing new skeletons, from S. coronopifolius. [5] Sphaerococcus coronopifolius is a bright red cosmopolitan alga, particularly interesting because it appears to be responsible for the production of a plethora of diterpenes of diverse molecular architectures.…”

Section: Introductionmentioning

confidence: 99%

“…[5] Sphaerococcus coronopifolius is a bright red cosmopolitan alga, particularly interesting because it appears to be responsible for the production of a plethora of diterpenes of diverse molecular architectures. [6][7][8][9][10][11][12][13][14][15] As part of our ongoing interest in the natural products chemistry of marine organisms of the Greek seas and their potential utilization in the development of new antifouling, antibacterial and anticancer agents, we have previously reported a number of new bioactive diterpenes, some possessing new skeletons, from S. coronopifolius. [16][17][18][19][20][21] Here we report the isolation and structure elucidation of three previously unknown rearranged diterpenes based on unprecedented tricyclic systems (Scheme 1), along with the in vitro evaluation of their antitumour activities.…”

Section: Introductionmentioning

confidence: 99%

Diterpenes with Unprecedented Skeletons from the Red Alga Sphaerococcus coronopifolius

et al. 2015

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Three previously unknown diterpenes -spirosphaerol (1), anthrasphaerol (2) and corfusphaeroxide (3) -have been isolated from the red alga Sphaerococcus coronopifolius. Their structures were elucidated by spectral analysis, including [a]General: Optical rotations were measured with a Perkin-Elmer model 341 polarimeter and a 10 cm cell. UV spectra were recorded with a Shimadzu UV-160A spectrophotometer. IR spectra were obtained with a Bruker Tensor 27 spectrometer. NMR spectra were recorded with Bruker AC 200 and Bruker DRX 400 spectrometers. Chemical shifts are given on a δ scale (ppm) with reference to the solvent signals. The 2D experiments (HSQC, HMBC, COSY, NOESY) were performed with use of standard Bruker pulse sequences. High-resolution ESI mass spectra were measured in positive mode with a Thermo Scientific LTQ Orbitrap Velos mass spectrometer (Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation). Low-resolution EI and CI mass spectra were measured with a Thermo Electron Corporation DSQ mass spectrometer and a Direct-Exposure Probe, with CH 4 as reagent gas. Vacuum liquid chromatography was performed with Kieselgel 60 (Merck), and gravity column chromatography was performed with Kieselgel 60H (Merck). Thinlayer chromatography (TLC) was performed with Kieselgel 60 F 254 aluminium support plates (Merck), and spots were visualized after spraying with H 2 SO 4 in MeOH (15 %, v/v) reagent followed by heating. HPLC separations were conducted with an Agilent 1100 model equipped with refractive index detector and a Kromasil 100 C18 5µ (250 ϫ 8 mm) HPLC reversed-phase column or a Supelco-Sil 5µ (250 ϫ 10 mm) HPLC normal-phase column. The structures in Figures 1, 2, and 3 were generated and optimised (energy: 37.26, 33.73 and 43.30 kcal mol -1 , respectively) by use of "HyperChem™ Professional 8.0.8" molecular modelling and simulation software (force field: MM+; optimisation algorithm: Polak-Ribiere). Plant Material: S. coronopifolius was collected by SCUBA diving in Liapades Bay, Corfu, Greece, at a depth of 8-15 m in June 2009. A voucher specimen is kept at the Herbarium of the Laboratory of Pharmacognosy and Chemistry of Natural Products, University of Athens (ATPH/MP0140).Extraction and Isolation: S. coronopifolius was initially freeze-dried (149.2 g dry weight) and then exhaustively extracted with CH 2 Cl 2 / MeOH mixtures (3:1) at room temperature. The combined extracts were concentrated to give a dark green residue (4.2 g), which was later subjected to vacuum liquid chromatography on silica gel, with use of a 2 % step gradient of cyclohexane/EtOAc elution sequence. Fraction F4 (4 % EtOAc in cyclohexane, 2.35 g) was fractionated by gravity column chromatography, with use of a 1 % step gradient of cyclohexane/EtOAc. Fraction F4.3 (8 % EtOAc in cyclohexane, 1.02 g) was further separated by reversed-phase HPLC, with use of www.eurjoc.org 2852 CH 3 CN as the mobile phase. Peak F4.3.9 (t R 11.4 min, 11.7 mg) was further purified by normal-phase HPLC, with use of 15 % Et...

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Three diterpenes from the red alga Sphaerococcus coronopifolius

Cited by 25 publications

References 6 publications

Cross-Metathesis of Methallyl Halides: Concise Enantioselective Formal Total Synthesis of (–)-Presphaerene

Cross-Metathesis of Methallyl Halides: Concise Enantioselective Formal Total Synthesis of (–)-Presphaerene

Antitumor and Antimicrobial Potential of Bromoditerpenes Isolated from the Red Alga, Sphaerococcus coronopifolius

Diterpenes with Unprecedented Skeletons from the Red Alga Sphaerococcus coronopifolius

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