Showing papers by "Jon Clardy published in 1997"
TL;DR: The roots of Delphinium denudatum have yielded a new diterpenoid alkaloid, 8-acetylheterophyllisine, in addition to the known alkaloids vilmorrianone, panicutine, denudatine, isotalatizidine, and condelphine, as well as 3-hydroxy-2-methyl-4H-pyran-4-one.
Abstract: The roots of Delphinium denudatum have yielded a new diterpenoid alkaloid, 8-acetylheterophyllisine (1), in addition to the known alkaloids vilmorrianone (2), panicutine (3), denudatine (4), isotalatizidine (5), and condelphine (6), as well as 3-hydroxy-2-methyl-4H-pyran-4-one (7). Compounds 1, 3, and 7 have not been isolated from this plant previously. The structures of compounds 1, 3, and 7 were determined through spectral and X-ray diffraction analyses. Compounds 1-3 have shown antifungal activity against a number of human pathogenic fungi.
101 citations
TL;DR: In this article, four new alkaloids, didemnimides A−D (1−4), possessing a novel indole−maleimide−imidazole carbon skeleton, have been identified as the major predator deterrents found in the chemically-defended Caribbean mangrove ascidian Didemnum conchyliatum.
Abstract: Four new alkaloids, didemnimides A−D (1−4), possessing a novel indole−maleimide−imidazole carbon skeleton, have been identified as the major predator deterrents found in the chemically-defended Caribbean mangrove ascidian Didemnum conchyliatum. The carbon skeleton of the didemnimides was identified by X-ray analysis of didemnimide A (1), while the structures of the related didemnimides B−D were subsequently assigned using combined spectral methods that emphasized one- and two-dimensional NMR methods. The didemnimides, in particular didemnimide D (4), are potent feeding deterrents against a natural assemblage of mangrove-specific carnivorous fish.
65 citations
TL;DR: In this article, chemical investigations of Cadlinaluteomarginata skin extracts, egg masses, and dietary sponges have led to the identification of the novel terpenoids cadlinaldehyde (30), spongian 32, seco-spongian 35, 20-acetoxy-12-marginatone (38), and lutenolide (39) from the nudibranch skin extracts.
Abstract: Chemical investigations of Cadlinaluteomarginata skin extracts, egg masses, and dietary sponges have led to the identification of the novel terpenoids cadlinaldehyde (30), spongian 32, seco-spongian 35, 20-acetoxy-12-marginatone (38), and lutenolide (39) from the nudibranch skin extracts, the new drimane sesquiterpenoid 1α,2α-diacetoxyalbicanyl acetate (40) from the nudibranch's egg mass, and the new sesquiterpenoids O-methyl-9-oxofurodysininlactone (47), 2-oxomicro-cionin-2-lactone (48), and O-methyl-2-oxomicrocionin-2-lactone (49), from the dietary sponge Pleraplysilla sp. The known terpenoids furodysinin (1), furodysin (16), marginatafuran (21), and 9,11-dihydrogracillin A (37), which have been frequently isolated from C. luteomarginata skin extracts, were found for the first time in extracts of the dietary sponges Pleraplysilla sp. and Aplysilla sp. One of the new terpenoids, cadlinaldehyde (30), has an unprecedented degraded sesterterpenoid skeleton. Keywords: nudibranch, sponge, terpenoids, structur...
45 citations
TL;DR: The parallel chemistry of these two specimens suggests that they are closely related taxonomically, and the physical properties as well as X-ray results confirming the structure and stereochemical features of these compounds are presented.
Abstract: A parallel study was conducted on two Indo-Pacific foliose sponges. The first specimen contains 3-hydroxy-20,22-dimethyl-20-deoxoscalarin (2), while the second contains 3-oxo-20,22-dimethyl-20-dioxoscalarin 8 (3). The physical properties as well as X-ray results confirming the structure and stereochemical features of these compounds are presented first. The difficulty we encountered in the taxonomic identification of these species is also discussed. One of our specimens is identical to material considered by different taxonomists as either Phyllospongia vermicularis or Dysidea vermicularis. The other is identified as Carteriospongia sp. We outline that the parallel chemistry of these two specimens suggests that they are closely related taxonomically.
23 citations
TL;DR: In this paper, the synthesis of 2-and 3-phospholenes as starting materials was discussed and structural analyses using 1H NMR and X-ray crystallography were conducted.
13 citations
12 citations
11 citations
TL;DR: In this article, four new alkaloids, didemnimides A−D (1−4), possessing a novel indole−maleimide−imidazole carbon skeleton, have been identified as the major predator deterrents found in the chemically-defended Caribbean mangrove ascidian Didemnum conchyliatum.
Abstract: Four new alkaloids, didemnimides A−D (1−4), possessing a novel indole−maleimide−imidazole carbon skeleton, have been identified as the major predator deterrents found in the chemically-defended Caribbean mangrove ascidian Didemnum conchyliatum. The carbon skeleton of the didemnimides was identified by X-ray analysis of didemnimide A (1), while the structures of the related didemnimides B−D were subsequently assigned using combined spectral methods that emphasized one- and two-dimensional NMR methods. The didemnimides, in particular didemnimide D (4), are potent feeding deterrents against a natural assemblage of mangrove-specific carnivorous fish.
9 citations
TL;DR: In this article, tridentatols A-C (1-3) with an uncommon sulfur-containing functional group have been isolated from the marine hydroid Tridentata marginata.
Abstract: Three novel phenolic metabolites, tridentatols A-C (1-3), with an uncommon sulfur-containing functional group have been isolated from the marine hydroid Tridentata marginata . The structures of the compounds were determined by interpretation of spectral data and a single crystal Xray diffraction study on tndentatol C. Ecological studies showed that tridentatol A deters feeding by a common hydroid predator. These metabolites also may function to protect T. marginata from damaging solar ultraviolet radiation.
4 citations