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  • 1
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    A new rearrangement of N-trifluoroacetoxyammonium salt under Polonovski–Potier reaction conditions: aziridinium versus iminium formation (2001)
    Elsevier
    Details
    Publication Date: 2001-05-01
    Print ISSN: 0040-4039
    Electronic ISSN: 1873-3581
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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  • 2
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    Antiprotozoal steroidal saponins from the marine sponge Pandaros acanthifolium (2011)
    Details
    Publication Date: 2021-05-19
    Description: The chemical composition of the Caribbean sponge Pandaros acanthifolium was reinvestigated and led to the isolation of 12 new steroidal glycosides, namely, pandarosides E-J (1-6) and their methyl esters (7-12). Their structures were determined on the basis of extensive spectroscopic analyses, including two-dimensional NMR and HRESIMS data. Like the previously isolated pandarosides A-D (13-16), the new compounds 1-12 share an unusual oxidized D-ring and a cis C/D ring junction. The absolute configurations of the aglycones were assigned by interpretation of CD spectra, whereas the absolute configurations of the monosaccharide units were determined by chiral GC analyses of the acid methanolysates. The majority of the metabolites showed in Vitro activity against three or four parasitic protozoa. Particularly active were the compounds 3 (pandaroside G) and its methyl ester (9), which potently inhibited the growth of Trypanosoma brucei rhodesiense (IC50 values 0.78 and 0.038 μM, respectively) and Leishmania donoVani (IC50’s 1.3 and 0.051 μM, respectively).
    Description: Published
    Description: Pandaros, steroidal saponins, structure elucidation, stereochemistry, antiprotozoal
    Keywords: Sponges ; Sponges
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 3
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    Polar Alkaloids from the Caribbean Marine Sponge Niphates digitalis (2011)
    Details
    Publication Date: 2021-05-19
    Description: A method involving flash chromatography, semi-preparative phenylhexyl RP HPLC-DAD-ELSD combined with analytic polar-RP HPLC-DAD, was applied to separate and purify six highly nitrogenated bases and a bicyclic amidine alkaloid, the major components of the marine sponge Niphates digitalis. Their structures were identified as 1,8-diazabicyclo[5.4.0]undec-7- ene (1), deoxycytidine (2), phenylalanine (3), adenosine (4), deoxyguanosine (5), adenine (6) and thymidine (7) on the basis of spectroscopic data analyses. This is the first report of these compounds in a marine sponge belonging to the Niphates genus and the first evidence of the presence of 1 from a natural source.
    Description: Published
    Description: Marine sponge, Niphates digitalis, nucleosides, nucleobases, antimalarial activity, cytotoxicity
    Keywords: Cytotoxicity ; Sponges ; Sponges ; Cytotoxicity
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 4
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    Steroidal glycosides from the marine sponge Pandaros acanthifolium (2011)
    Details
    Publication Date: 2021-05-19
    Description: The chemical composition of the Caribbean sponge Pandaros sp. was investigated and led to the isolation of seven new steroidal glycosides namely pandarosides A-D (1, 3, 4 and 6) along with the three methyl esters of pandarosides A, C, and D (2, 5 and 7). Their structures were characterized as 3β-[β-glucopyranosyl-(1→2)-β-glucopyranosyloxyuronic acid]-16-hydroxy- 5α,14β-poriferast-16-ene-15,23-dione (1) and its methyl ester (2), 3β-[β- glucopyranosyloxyuronic acid]-16-hydroxy-5α,14β-poriferast-16-ene-15,23-dione (3), 3β-[β- glucopyranosyl-(1→2)-β-glucopyranosyloxyuronic acid]-16-hydroxy-5α,14β-cholest-16-ene- 15,23-dione (4) and its methyl ester (5), 3β-(β-glucopyranosyloxyuronic acid)-16-hydroxy- 5α,14β-cholest-16-ene-15,23-dione (6) and its methyl ester (7) on the basis of detailed spectroscopic analyses, including 2D NMR and HRESI-MS studies. Pandarosides A-D and their methyl esters (1-7) are all characterized by a rare 2-hydroxycyclopentenone D-ring with a 14β configuration.
    Description: Published
    Description: Marine sponge, Pandaros, steroidal glycosides, structure elucidation, stereochemistry
    Keywords: Sponges ; Sponges
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 5
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    Bromopyrrole alkaloids from the Caribbean sponge Agelas cerebrum (2011)
    Sociedade Brasileira de Química
    Details
    Publication Date: 2021-05-19
    Description: Bioguided fractionation of Agelas cerebrum crude extract resulted in isolation of four bromopyrrole and four bromopyrrole aminoimidazole alkaloids, identified as 5-bromopyrrole-2-carboxylic acid (1), 4-bromopyrrole-2-carboxylic acid (2), 3,4-bromopyrrole-2-carboxylic acid (3), 4,5-bromopyrrole-2-carboxylic acid (4), oroidin (5), bromoageliferin (6), dibromoageliferin (7) and dibromosceptrin (8) on the basis of spectroscopic data analyses (UV, IR, HRMS, 1D and 2D NMR) and comparison with literature data. This is the first report of compounds 2 and 3 in a marine sponge belonging to the Agelas genus and the first evidence of the presence of 1 from a natural source.
    Description: Published
    Description: Agelas cerebrum, bromopyrrole alkaloids, antitumoral, antiprotozoal activity
    Keywords: Chemistry ; Alkaloids ; Sponges ; Alkaloids ; Sponges ; Chemistry
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 6
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    Parazoanthines A-E: Hydantoin Alkaloids from the Mediterranean Sea Anemone Parazoanthus axinellae (2011)
    Details
    Publication Date: 2021-05-19
    Description: Five new hydantoin alkaloids, named parazoanthines A-E (1-5), were isolated as the major constituents of the Mediterranean sea anemone Parazoanthus axinellae. Their structural elucidation was achieved through NMR spectroscopic and mass spectrometric analyses. The absolute configuration of the chiral compounds 1 and 4 was determined by comparison between experimental and TDDFT calculated CD spectra. The configuration of the trisubstituted double bond of 2, 3, and 5 was deduced from the 3JH6-C4 coupling constant value. This family of alkaloids represents the first example of natural 3,5- disubstituted hydantoins which do not exhibit a methyl at N-3. All compounds were tested for their natural toxicity (Microtox® assay) and parazoanthine C (3) exhibited the highest natural toxicity. 3 Relatively few chemical studies of zoanthids have been reported so far, despite evidence of their rich natural products chemistry.1 Colonial sea anemones of the genus Parazoanthus have been identified in almost all the oceans and they often have been described as epibionts of marine sponges belonging to the Agelas or Axinella genera. As sponges are known to exude toxic compounds, these zoanthids must have developed adaptative tools to minimize effects of such toxins. Two groups of compounds have been described from Parazoanthus species: fluorescent guanidine alkaloids of the zoanthoxanthin families,2-7 and ecdysteroids.8 As part of an ongoing research program to investigate the chemodiversity of Mediterranean invertebrates,9 specimens of Parazoanthus axinellae were collected near Marseilles (Plane island) as epibionts of the sponge Axinella damicornis. Because the LC–MS analyses of their crude extracts evidenced brominated compounds as major constituents, we decided to undertake the full chemical study of this species from which only zoanthoxanthins have been previously described.2,3 We report herein the isolation and structural characterization of a new class of alkaloids named parazoanthines A-E (1-5) with a rare 3,5-disubstituted hydantoin core.
    Description: Published
    Description: sea anemones, Parazoanthus, structure elucidation, stereochemistry
    Keywords: Alkaloids ; Alkaloids
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 7
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    Acanthifoliosides, minor steroidal saponins from the Caribbean marine sponge Pandaros acanthifolium (2011)
    Details
    Publication Date: 2021-05-19
    Description: Seven novel steroid glycosides, acanthifoliosides A-F (1-6) and the methyl ester of 6 (7), were isolated from the marine sponge Pandaros acanthifolium as minor components. Acanthifoliosides are characterized by a rare C-15 and C-16 oxidized D ring which was previously found in saponins produced by starfishes. Very uncommon is the presence of additional sugar residues at C-15 or C-16. Their structures were determined on the basis of extensive spectroscopic analyses, including two-dimensional NMR and HRESIMS data. The absolute configurations of the aglycones were assigned by comparison between experimental and TDDFT calculated CD spectra of 1, whereas the absolute configurations of the monosaccharide units were determined by chiral GC analyses of the acid methanolysates. Some of the acanthifoliosides exhibit moderate antiprotozoal activity but to a lesser extent than the most potent pandarosides.
    Description: La version original de este artículo está disponible en la Editorial Elsevier
    Description: Published
    Description: steroidal saponin, Pandaros, NMR, Circular dichroism
    Keywords: Sponges ; Sponges
    Repository Name: AquaDocs
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