Calophyllum products. III. Structure of blancoic acids

Stout, George H.; Sears, Karl D.

doi:10.1021/jo01275a038

Cited by 22 publications

(9 citation statements)

References 4 publications

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“…12 Indepth chemical analysis of the pyranocoumarins present in nine additional extracts led to the isolation of five compounds. The isolated coumarins included cordatolide A (4); tricyclic, or D-ring opened, calanolide E (7, originally isolated with the calanolides); one of its diastereomers, calanolide E2 (9); cordatolide E (10) with a methyl substituent at C-4; calanolide F (11), a new C-10 epimer of (+)-calanolide A; and pseudocordatolide C ( 12), the pyranoring reversed analogue with a C-4 methyl substituent. This was the first isolation of compounds 9-12; details of their isolation and structure elucidation have been reported elsewhere.…”

Section: Pyranocoumarins Frommentioning

confidence: 99%

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Pyranocoumarins from Tropical Species of the Genus Calophyllum: A Chemotaxonomic Study of Extracts in the National Cancer Institute Collection

et al. 1998

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(+)-Calanolide A, a novel dipyranocoumarin from the Malesian tree Calophyllum lanigerum var. austrocoriaceum, and a closely related compound, (-)-calanolide B, isolated from Calophyllum teysmannii var. inophylloide, are representatives of a distinct class of nonnucleoside HIV-1 specific reverse-transcriptase inhibitor under development as an AIDS chemotherapeutic. NCI repository specimens totalling 315 organic extracts from 31 taxa of Calophyllum were analyzed for related pyranocoumarins using a simple TLC system. A total of 127 extracts was initially classified as "positive"; eight out of the 31 taxa examined, representing perhaps 28 species already described (1/7-1/8 of all the species in this genus), contained prenylated coumarins, suggesting that these compounds, while sometimes abundantly present, are not widespread in the genus. Representative members of the TLC-positive extracts were partitioned between CH2C12 and 25% aqueous MeOH; the CH2C12-soluble materials were then analyzed by TLC and 1H NMR to confirm the presence of pyranocoumarins. The anti-HIV activity of the partitioned extracts are also presented. This study suggested that there are several distinctive coumarin chemotaxonomic markers distinguishing species of this genus.

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Section: Pyranocoumarins Frommentioning

confidence: 99%

“…Plants from the genus Calophyllum (Guttiferae, Clusiaceae) have proven to be a rich source of natural products, including xanthones, − steroids, triterpenes, , coumarins, − and benzopyrans . In 1992, we reported a series of dipyranocoumarins, the calanolides, from C. lanigerum var.…”

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confidence: 99%

Pyranocoumarins from Tropical Species of the Genus Calophyllum: A Chemotaxonomic Study of Extracts in the National Cancer Institute Collection

et al. 1998

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“…Although compound 1 is herewith reported for the first time as a natural product, it is a principle building block of Calophyllum metabolites [25][26][27][28][29][30] and thus a precursor towards the total synthesis of an anti-HIV-1 compound, (±)-calanolide A [31]. The absolute configuration of 1, (2R,3R)-5,7-dihydroxy-2,3-dimethyl-4-chromanone, was inferred from the already established configuration of papuanic acid isolated from Calophyllum papuanum [28,32].…”

Section: Resultsmentioning

confidence: 99%

<b>PHLOROGLUCINOL DERIVATIVES AND FLAVONES FROM <i>HELICHRYSUM PARONYCHIOIDES</i></b>

Mutanyatta-Comar

Phale

Abegaz

et al. 2006

Bull. Chem. Soc. Eth.

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Investigation of Helichrysum paronychioides afforded a total of nine compounds: 4 phloroglucinol derivatives, 2 of which are novel natural products, and 5 flavone derivatives. Structures were established by various spectroscopic techniques (NMR, MS, UV, IR, CD) and by comparison with literature data for the known compounds. The four phloroglucinols, trans-(2R,3R)-5,7-dihydroxy-2,3-dimethyl-4-chromanone (1), 2-butanoyl-4-prenyl-1-methoxy phloroglucinol (2), 2-(2-methylpropanoyl)-4-prenylphloroglucinol (3) and 2-(2-methyl-butanoyl)-4-prenylphloroglucinol (4) were screened for antioxidant activity against Cu-induced LDL oxidation. Compound 4 was found to be the most active inhibiting LDL oxidation at all concentrations (0.5-10 µM) while the other three showed moderate to no activity.

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“…Acidic hydrolysis of 5 yielded glucose and rhamnose in addition to its aglycone. The planar structure of 5 was established on the basis of its HMBC spectrum, in which 13 In addition to the new compounds 1-5, 17 known compounds were also isolated and characterized as calanolide E 2 , 17 chapelieric acid, 18 apetalic acid, 19 isocalolongic acid, 20 blancoic acid, 21 2-hydroxyxanthone, 22 4-hydroxyxanthone, 23 1,5-dihydroxy-3-methoxyxanthone, 24 3-hydroxy-4-methoxyxanthone, 25 3,4-dihydroxyxanthone, 26 2-methoxyxanthone, 27 6-(4-hydroxy-3-methylbut-2-enyl)-1,5-dihydroxyanthone, 28 1,2,3-trihydroxy-5-methoxyxanthone, 29 2,7-dihydroxy-1,8-dimethoxyxanthone, 30 1,3-dimethoxy-5hydroxyxanthone, 31 1-methoxy-2-hydroxyxanthone, 27 and 1,8-dimethoxy-2-hydroxyxanthone 32 by comparison with data in the literature.…”

Section: Resultsmentioning

confidence: 99%

Selective Cyclooxygenase-2 Inhibitors from Calophyllum membranaceum

et al. 2005

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Chemical investigation of the anti-inflammatory Chinese folk medicine Calophyllum membranaceum has resulted in the isolation and characterization of three new xanthones (1-3), one new biphenyl C-glycoside (4), and one new phenylethanoid glycoside (5) along with 17 known compounds. Their structures were characterized on the basis of spectroscopic and chemical methods. Two xanthones, 2,6-dihydroxy-1,7-dimethoxyxanthone (1) and 3,4-dihydroxyxanthone, were found to exhibit selective inhibitory activity against cyclooxygenase-2 (IC(50)=2.99 and 1.80 microM) in vitro.

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Calophyllum products. III. Structure of blancoic acids

Cited by 22 publications

References 4 publications

Pyranocoumarins from Tropical Species of the Genus Calophyllum: A Chemotaxonomic Study of Extracts in the National Cancer Institute Collection

Pyranocoumarins from Tropical Species of the Genus Calophyllum: A Chemotaxonomic Study of Extracts in the National Cancer Institute Collection

<b>PHLOROGLUCINOL DERIVATIVES AND FLAVONES FROM <i>HELICHRYSUM PARONYCHIOIDES</i></b>

Selective Cyclooxygenase-2 Inhibitors from Calophyllum membranaceum

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