The Photosensitized Oxygenation of Furanoeremophilanes. III. The Transformations to the Skeletally Isomeric Lactones from Furanofukinol

Naya, Keizo; Shimizu, Mitsuaki; Nishio, Hideki; Takeda, Motonori; Oka, Shogo; Hirota, K.

doi:10.1246/bcsj.64.1071

Cited by 18 publications

(11 citation statements)

References 17 publications

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“…Lactones, which only differed in the configuration at C 8 , exhibited CD spectra with opposite directions (nonsteroid-like 8a-stereoisomer 2; steroid-like 8b-stereoisomer 1). [43][44][45][46] In agreement with these observations, the CD spectra of 7 and 8 had negative signs with minima at k 5 224.0 nm (De 5 29, 7) and k 5 223.8 nm (De 5 29, 8), respectively. Both CD spectra were almost superimposable, indicating that the influence of the ester side chain on the CD may be negligible (Fig.…”

Section: Experimental CD Spectroscopy Of Compounds 2 To 10supporting

confidence: 79%

Absolute configuration of eremophilane sesquiterpenes from Petasites hybridus: Comparison of experimental and calculated circular dichroism spectra

Bodensieck¹,

Fabian²,

Kunert³

et al. 2009

Chirality

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In-depth conformational analyses of 10 known eremophilane (= (1S,4aR,7R,8aR)-decahydro-1,8a-dimethyl-7-(1-methylethyl)napththalene) sesquiterpenes, 1-10, from Petasites hybridus were performed with molecular mechanics as well as density functional theory methods. Electronic transition energies and rotational strengths of these eight eremophilane lactones and two petasins were calculated by time-dependent density functional theory (B3PW91/TZVP). The absolute configurations of the constituents could be assigned by comparison of their simulated and experimental circular dichroism (CD) spectra in methanol as (4S,5R,8S,10R) (1, 2), (2R,4S,5R,8S,10R) (3, 4, 5), (2R,4S,5R,8R,9R,10R) (6), (2R,4S,5R,8R,10R) (7, 8), and (3R,4R,5R) (9, 10). Single-crystal X-ray diffraction data of 8beta-hydroxyeremophilanolide ((8S)-8-hydroxyeremophil-7(11)-en-12,8-olide) (1) served as starting point for the theoretical conformational calculations of the 8beta-epimers of the eremophilane lactones. Experimental CD spectra as well as (1)H NMR spectra of compound 1 in methanol were considerably dependent on sample concentration.

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Section: Experimental CD Spectroscopy Of Compounds 2 To 10supporting

confidence: 79%

Absolute configuration of eremophilane sesquiterpenes from Petasites hybridus: Comparison of experimental and calculated circular dichroism spectra

Bodensieck¹,

Fabian²,

Kunert³

et al. 2009

Chirality

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“…Then the chemical shift of H-23 was downfield from that of H-24, suggesting that 4 possessed a cis -eremophilanyl unit and a β-oriented OH-19. Based on the Naya rules, − the homoallylic coupling between H-13α and H-22 observed in the 1 H– 1 H COSY spectrum indicated that OH-21 was β-configurated. Furthermore, the key NOESY correlation of H-20α/H-1 demonstrated the α-orientation of C 3 -carbonyl group.…”

Section: Resultsmentioning

confidence: 79%

Parasubindoles A–G, Seven Eremophilanyl Indoles from the Whole Plant of Parasenecio albus

Zhou

Liu

et al. 2018

J. Org. Chem.

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“…Furthermore, the absolute stereochemistry of 1 was elucidated by applying the empirical rule for the α,β-unsaturated γ-lactone of eremophilane-type sesquiterpenoids in circular dichroism (CD) spectrum. The negative Cotton effects, observed at 245 nm, substantiated the absolute configuration of C-8 to be R. 8,10) Culcitiolides F and G (2, 3) were purified as an inseparable mixture of two structural isomers. The molecular formulas of these isomers were established by HR-FAB-MS as C 21 4,5,7,11) with the ratio of 1 to 1.…”

Section: Resultsmentioning

confidence: 89%

“…3). The NOE enhancements for H-14/H-3 β , H-14/H-6, H-14/H-10, H-15/H-3 β and H-4/H-6 indicated that these compounds contain a cis-decalin ring system with a steroidal-like conformation 7,10) and that each acyl group was in the β-orientation. Furthermore, the direction of methoxy group (C-16) was determined to be β-orientation according to the above mentioned rules reported by Naya et al [8][9][10] Based on these results, the relative stereochemistries of culcitiolides F and G were determined as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Culcitiolides E–J, Six New Eremophilane-Type Sesquiterpene Derivatives from <i>Senecio culcitioides</i>

Mitsui

Hayashi

Kawai

et al. 2013

CHEMICAL & PHARMACEUTICAL BULLETIN

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Culcitiolides E-J (1-6), six new eremophilane-type sesquiterpenes, were isolated from the stem of Senecio culcitioides Sch. Bip. (Asteraceae). The structures were determined by detailed NMR spectral analysis. The inhibitory activities of these compounds against nuclear factor κB (NF-κB)-dependent gene expression were assessed. Culcitiolides E, H, and I potently inhibited NF-κB-induced gene expression at 20 µm.Key words Senecio culcitioides; eremophilane; culcitiolide; nuclear factor κB Senecio culcitioides Sch. Bip. is distributed throughout the Peruvian Andes in South America at an altitude of 4500-5000 m. S. culcitioides belongs to the family Asteraceae and has been used as a traditional folk medicine to treat cough, bronchitis and asthma.1-3) Nuclear factor κB (NF-κB) is a transcription factor and functions as a key regulatory element in inflammatory and immune responses and in cancer. During our search for new classes of inhibitors of NF-κB derived from natural products, we previously isolated culcitiolides A-D, eremophilane-type sesquiterpenoids from the stem of the previously uninvestigated plant S. culcitioides, and we showed that culcitiolides C and D are potent NF-κB inhibitors. 4) Our continuous effort to identify NF-κB inhibitors in S. culcitioides led to the isolation of six new eremophilane-type sesquiterpenoids exhibiting potent NF-κB inhibitory activity. Herein, we describe the isolation and structural elucidation of culcitiolides E-J and the evaluation of their inhibitory activities against NF-κB-dependent gene expression.

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The Photosensitized Oxygenation of Furanoeremophilanes. III. The Transformations to the Skeletally Isomeric Lactones from Furanofukinol

Cited by 18 publications

References 17 publications

Absolute configuration of eremophilane sesquiterpenes from Petasites hybridus: Comparison of experimental and calculated circular dichroism spectra

Absolute configuration of eremophilane sesquiterpenes from Petasites hybridus: Comparison of experimental and calculated circular dichroism spectra

Parasubindoles A–G, Seven Eremophilanyl Indoles from the Whole Plant of Parasenecio albus

Culcitiolides E–J, Six New Eremophilane-Type Sesquiterpene Derivatives from <i>Senecio culcitioides</i>

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