Tricalysiolides A–F, new rearranged ent-kaurane diterpenes from Tricalysia dubia

Nishimura, Koichi; Hitotsuyanagi, Yukio; Sugeta, Noriko; Sakakura, Kei-ichi; Fujita, Kazuya; Fukaya, Haruhiko; Aoyagi, Yutaka; Hasuda, Tomoyo; Kinoshita, Takeshi; He, Dong-Hui; Otsuka, Hideaki; Takeda, Yoshio; Takeya, Koichi

doi:10.1016/j.tet.2005.11.024

Cited by 28 publications

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References 9 publications

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“…Since a series of compounds was isolated from the same plant material, kaurane must have an entio-skeleton and glucose of the D-series. [3][4][5][6] These suppositions were confirmed by evidence that acid hydrolysis of 4 gave D-glucose and then in the 13 C-NMR spectra, chemical shifts of the A-rings, to which the D-glucose was attached, of tricalysiolides P (4) and H (10) showed essentially the same chemical shifts. Therefore the structure of tricalysioside P (4) was elucidated to be ent-1b,17-dihydroxykauran-19-oic acid 1-O-b-D-glucopyranoside, as shown in Fig.…”

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confidence: 83%

“…5,6) Further extensive investigation of the same plant material afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with one megastigmane glucoside, two monoterpene glucosides (1, 2), [7][8][9] and sammangaoside B (3).…”

Section: )mentioning

confidence: 99%

“…3,4) Non-glycosidic rearranged ent-kauranes were also isolated from the same plant species. 5,6) Further extensive investigation of the same plant material afforded five new ent-kaurane glucosides (4)(5)(6)(7)(8) and one new labdane glucoside (9), together with one megastigmane glucoside, two monoterpene glucosides (1, 2), [7][8][9] and sammangaoside B (3). 10) This paper deals with their structural elucidation and revision of the stereostructure of sammangaoside B.…”

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confidence: 99%

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Tricalysiosides P-U: Ent-kaurane Glucosides and a Labdane Glucoside from Leaves of Tricalysia dubia OHWI

Otsuka

Shitamoto

et al. 2007

Chem. Pharm. Bull.

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The approximately 50 species of Tricalysia (Syn. Canthium) are found in subtropical and tropical areas of Asia and Africa. Some species are used for medicinal purposes, e.g. the roots, leaves, and stem bark of Canthium subcordatum are used as folk medicines in Africa. 1)Tricalysia dubia (LINDL.) OHWI (Rubiaceae) is an evergreen shrub or tree that grows to a height of about 2-4 m. It is distributed in the south of China, Taiwan, and Okinawa. 2)In the course of our study on Okinawa's promising resource plants, the constituents of the title plant, T. dubia, were investigated.In previous papers, the structural elucidation of seven rearranged ent-kaurane glucosides, tricalysiosides A-G, and eight ent-kaurane glucosides, named tricalysiosides H-O, from leaves of T. dubia was reported.3,4) Non-glycosidic rearranged ent-kauranes were also isolated from the same plant species. 5,6) Further extensive investigation of the same plant material afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with one megastigmane glucoside, two monoterpene glucosides (1, 2), [7][8][9] and sammangaoside B (3).10) This paper deals with their structural elucidation and revision of the stereostructure of sammangaoside B. Results and DiscussionAir-dried leaves of T. dubia were extracted with MeOH three times and the concentrated MeOH extract was partitioned with solvents of increasing polarity. The 1-BuOH-soluble fraction was separated by various chromatographic procedures including column chromatography (CC) on a highly porous synthetic resin (Diaion HP-20), normal silica gel and reversed-phase octadecyl silica gel (ODS) CC, then droplet counter-current chromatography (DCCC) to afford six diterpenoid glucosides, named tricalysiosides P-U (4-9) (Fig. 1), together with one megastigamne glucoside, two monoterpene glucosides (1, 2), [7][8][9] and summangaoside B (3).10) The details and yields are given in the Experimental section. The structures of tricalysiosides P-U (4-9) were elucidated by spectroscopic analyses and comparison with tricalysiosides previously isolated based on spectroscopic evidence. Sammangaoside B (3), [a] D Ϫ35.0°, was first isolated from Clerodendrum inerme but the stereochemistry of its six-membered ring portion remained to be determined. Phase-sensitive NOE experiments supported the previously reported relative structure of the ring system, as depicted in the literature. 10) Application of modified Mosher's method 11) to the aglycone led to revision of the absolute configuration of the 9-position to S (Fig. 2) Further extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of Tricalysia dubia afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with a known megastigmane glucoside, sammangaoside B (1), and monoterpene glucosides (2, 3). The structures of the new compounds were elucidated by analyses of one-and two-dimensional NMR spectroscopic data. The absolute configuration of the 9-position of sammangaoside B was revised to ...

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confidence: 99%

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Tricalysiosides P-U: Ent-kaurane Glucosides and a Labdane Glucoside from Leaves of Tricalysia dubia OHWI

Otsuka

Shitamoto

et al. 2007

Chem. Pharm. Bull.

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“…On phytochemical investigation of the leaves of T. dubia, many rearranged ent-kauranes and entkaurane glycosides were isolated [2,3]. Non-glycosidic rearranged ent-kauranes were also isolated from its woods [4], as well as its leaves [5].…”

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confidence: 99%

“…tricalysiolides A-E (3-7) [4], stigmast-4-en6b-ol-3-one (8) [6], (+)-pinoresinol (9) [7], scopoletin (10) [8] and syringaldehyde (11) [9]. The structures of the new compounds were elucidated from spectroscopic evidence and those of the known compounds were determined by comparison of the physical data with those reported.…”

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confidence: 99%

Rearranged ent-kauranes from the stems of Tricalysia dubia and their biological activities

et al. 2008

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From the EtOAc-soluble fraction of an MeOH extract of the stems of Tricalysia dubia, two new rearranged ent-kaurane derivatives, named tricalysiolides H and I, were isolated, together with five known rearranged ent-kauranes, i.e. tricalysiolides A-E, stigmast-4-en-6beta-ol-3-one, (+)-pinoresinol, scopoletin and syringaldehyde. Their structures were elucidated from spectroscopic evidence, and their cytotoxicity toward KB cells and P-gp inhibitory activity were assayed.

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Enantioselective Multicomponent Synthesis of Fused 6–5 Bicyclic 2‐Butenolides by a Cascade Heterobicyclisation Process

Suero¹,

Campa²,

Torre-Fernández³

et al. 2012

Chemistry A European J

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The successive coupling of an alkoxy(aryl/heteroaryl)carbene complex of chromium with either a ketone or an imide lithium enolate and then a 3-substituted (H, TMS, PhCH(2), PhCH(2)CH(2), Me) propargylic organomagnesium reagent has afforded novel hydroxy-substituted bicyclic [4.3.0]-γ-alkylidene-2-butenolides with three modular points that has allowed the efficient introduction of molecular complexity, including a homopropargylic alcohol core. The selective formation of these five- or six-component heterobicyclisation products is the result of the regioselective integration of the Grignard reagent as a propargyl fragment followed by a cascade CO/alkyne/CO insertion, ketene trapping and elimination sequence. By using lithium enolates of chiral N-acetyl-2-oxazolidinones and the corresponding propargylic organocerium reagents, both enantiomers of these bicyclic heterocycles were efficiently prepared with very high enantiomeric purity. Architecturally, these fused bicyclic butenolides are characterised by a highly unsaturated and oxygenated core and they exhibit strong blue fluorescence in solution.

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Tricalysiolides A–F, new rearranged ent-kaurane diterpenes from Tricalysia dubia

Cited by 28 publications

References 9 publications

Tricalysiosides P-U: Ent-kaurane Glucosides and a Labdane Glucoside from Leaves of Tricalysia dubia OHWI

Tricalysiosides P-U: Ent-kaurane Glucosides and a Labdane Glucoside from Leaves of Tricalysia dubia OHWI

Rearranged ent-kauranes from the stems of Tricalysia dubia and their biological activities

Enantioselective Multicomponent Synthesis of Fused 6–5 Bicyclic 2‐Butenolides by a Cascade Heterobicyclisation Process

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