Identification of the Eight‐Membered Heterocycles Hicksoanes A–C from the Gorgonian <i>Subergorgia hicksoni</i>

Řezanka, Tomáš; Hanŭs, L; Dembitsky, Valery M.; Sigler, Karel

doi:10.1002/ejoc.200700645

Cited by 21 publications

(9 citation statements)

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“…The product of the reaction was isolated as a colourless solid (yield: 60%) and identified as the eight-membered O,N,B-heterocycle 5 by X-ray diffraction analysis (see below) and mass spectrometry (EI-MS: m/z = 641. 3 39 and falls into a range typical for borinate esters (R 2 BOR). 40 The one, as observed for organic azides.…”

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O,N,B-Containing eight-membered heterocycles by ring expansion of boroles with nitrones

et al. 2015

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By a ring expansion reaction of boroles with nitrones a straightforward route to eight-membered O,N,B-containing ring systems was developed, which present a new structural motif in heterocyclic chemistry. Formally, these compounds can be considered as BN-analogues of eight-membered ring ethers containing three double bonds. The X-ray crystallographic data of a series of these oxazaborocine derivatives show that they adopt a boat conformation in the solid state.

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“…1,2 These bioactive molecules are produced e.g. in higher plants or marine organisms 3,4 thus prompting their exploration and making them attractive synthetic targets. [5][6][7] In particular, eight-membered rings have attracted attention due to their unique symmetric and conformational properties.…”

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confidence: 99%

O,N,B-Containing eight-membered heterocycles by ring expansion of boroles with nitrones

et al. 2015

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“…Fragilisinin J 128 exhibited potent antifouling activities at nontoxic concentrations with EC 50 values of 11.9 mM. 132 Novel eight-membered heterocycles named hicksoanes A-C (131-133) 133 were isolated from the Red Sea gorgonian Subergorgia hicksoni (Gulf of Aqaba, Eilat, Israel). Hicksoanes A-C (131)(132)(133) showed antifeeding activities against goldsh at natural concentrations of 10.0 mg mL À1 .…”

Section: Mangaladossmentioning

confidence: 99%

“…132 Novel eight-membered heterocycles named hicksoanes A-C (131-133) 133 were isolated from the Red Sea gorgonian Subergorgia hicksoni (Gulf of Aqaba, Eilat, Israel). Hicksoanes A-C (131)(132)(133) showed antifeeding activities against goldsh at natural concentrations of 10.0 mg mL À1 . The biosynthesis of hicksoanes A-C (131-133) proceeds presumably under the participation of haloperoxidases and nonribosomal peptide biosynthetic machinery.…”

Section: Mangaladossmentioning

confidence: 99%

Naturally occurring organoiodines

et al. 2014

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“…Based on the above data, the structure of 3 was elucidated to be 2,3,5,6,11,11b-hexahydro-2-hydroxy-1H-indolizino [8,7-b]indole-2-carboxylic acid (trivial name 2-hydroxyharmicine-2-carboxylic acid). Rarely, indole-type alkaloids were isolated from gorgonians, the only example being hicksoanes A -C from the gorgonian Subergorgia hicksoni [12].…”

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New Steroids and a New Alkaloid from the Gorgonian Isis minorbrachyblasta: Structures, Cytotoxicity, and Antilarval Activity

Miao

Gao

et al. 2010

Helvetica Chimica Acta

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Two new polyoxygenated steroids, (1a,3b,7a,11a,12b)-gorgost-5-ene-1,3,7,11,12-pentol 12-acetate (1) and 11-O-acetyl-22-epihippuristanol (2), and a new alkaloid, 2,3,5,6,11,11b-hexahydro-2-hydroxy-1H-indolizino [8,7-b]indole-2-carboxylic acid (3), together with three known compounds, 22-epihippuristanol (4), hippuristanol (5), and tryptamine (6), were isolated from the EtOH/CH 2 Cl 2 extracts of the South China Sea gorgonian Isis minorbrachyblasta. The structures of the new compounds were determined by spectroscopic methods. Compound 1 showed weak cytotoxicity against A549, HONE1, and HeLa cancer cell lines and strong antilarval activity towards Bugula neritina larvae with an EC 50 value of 5.8 mg/ml. Compound 5 showed moderate cytotoxicity against A549, HONE1, and HeLa cell lines, and the epimer mixture 4/5 (weight ratio 3 : 2) exhibited potent cytotoxicity against A549 and HONE1 cell lines with IC 50 values of 4.2 and 4.8 mg/ml, which indicated that epimers 4 and 5 might have a synergistic effect on their cytotoxicity against A549 and HONE1 cell lines.Introduction. -Both Isis minorbrachyblasta and I. hippuris belong to the Isis genus, Isididae family of gorgonian corals. There are reports that I. hippuris is unique concerning its steroidal constituents that can be characterized as of the hippurin or hippuristanol type having a spiroketal [1 -4], of the gorgosterol type possessing a cyclopropane [5 -7], and of the hippuristerone type containing a 3-keto function [4] [8]. These types also differ in the side-chain alkylation pattern. Some of these compounds have been reported to have significant biological activities, e.g., hippuristanol and (2a)-2-hydroxyhippuristanol showed 50% inhibition (in vitro) of DBA/MC fibrosarcoma at 0.8 and 0.1 mg/ml [2], several hippuristanol-type steroids showed potent cytotoxicity against P-388, A549, HT29, and MEL28 cancer cell lines [4], and several gorgosterol-type steroids showed moderate activity against drug-resistant cells (KBC2) expressing P-glycoprotein [7]. However, there were no reports about the chemical constituents of Isis minorbrachyblasta. In our present investigation on the chemical constituents of the South China Sea gorgonian I. minorbrachyblasta Zou 1991, two new steroids, (1a,3b,7a,11a,12b)-gorgost-5-ene-1,3,7,11,12-pentol 12-acetate (1) and 11-O-acetyl-22-epihippuristanol (2), and a new alkaloid, 2,3,5,6,11,11b-hexahydro-2-hydroxy-1H-indolizino [8,7-b]indole-2-carboxylic acid (3), were obtained, together with the three known compounds 22-epihippuristanol (4) [4], hippuristanol (5) [2] [4], and tryptamine (6) [9]. The cytotoxicity of 1, 5, and the

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Identification of the Eight‐Membered Heterocycles Hicksoanes A–C from the Gorgonian Subergorgia hicksoni

Cited by 21 publications

References 43 publications

O,N,B-Containing eight-membered heterocycles by ring expansion of boroles with nitrones

O,N,B-Containing eight-membered heterocycles by ring expansion of boroles with nitrones

Naturally occurring organoiodines

New Steroids and a New Alkaloid from the Gorgonian Isis minorbrachyblasta: Structures, Cytotoxicity, and Antilarval Activity

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