Conformational Study of Geissoschizine Isomers and Their Model Compounds

Lounasmaa, Mauri; Hanhinen, Pirjo

doi:10.3987/rev-98-512

Cited by 15 publications

(18 citation statements)

References 14 publications

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“…Intermediate 20a, in which a large malonate residue assumes an equatorial orientation, would be predominant over conformer 20b, resulting in the formation of compound 21. 19(Z) isomer (23) (22) to the monoaldehyde with DIBALH furnished (±)-geissoschizine (13) in 72% yield.…”

Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 98%

“…Geissoschizine (13), a demethyl derivative of 3, is one of the key intermediates in the biosynthesis of monoterpenoid indole alkaloids [1,11]. Despite the apparent simplicity of its chemical structure, however, its conformation has been the subject of a long debate [12,13]. Our recent study using density functional theory calculations of the hitherto proposed structures of geissoschizine has indicated that structure 13a (Fig.…”

Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 99%

“…Under this condition, desired compound (30) was obtained in 30% yield together with two structurally interesting side products (35) and (36) in 22% and 35% yields, respectively. Synthetic compound 30 was revealed to be identical with the natural product by comparison of their chromatographic behavior as well as their UV, 1 H-NMR, 13 C-NMR, and mass spectra. Compound 35 exhibited characteristic UV absorption bands (230.5, 366.5 nm), suggesting the presence of a 2-aminoacetophenone chromophore, and was elucidated to be the 2,7-seco derivative by analyzing the NMR data.…”

Section: -2 Alkaloids In Uncaria Attenuatamentioning

confidence: 99%

“…From the : Corynoxeine (7) : Isorhynchophylline (8) : Isocorynoxeine (9) Corynanthé-type Oxindoles (1) : Hirsuteine (2) : Dihydrocorynantheine (4) : Corynantheine (5) leaves of this plant, glycoindole alkaloids, namely, strictosamide (10), vincoside lactam (11), and rhynchophine (12), have been isolated [10]. Geissoschizine (13), a demethyl derivative of 3, is one of the key intermediates in the biosynthesis of monoterpenoid indole alkaloids [1,11]. Despite the apparent simplicity of its chemical structure, however, its conformation has been the subject of a long debate [12,13].…”

Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 99%

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Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

Takayama¹,

Kitajima²,

Kogure

2005

COC

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A number of monoterpenoid indole and oxindole alkaloids have been isolated from botanical sources, and many of them have been found to possess significant pharmacological activities and are utilized as key lead compounds in new drug development. In this review, the recent results of our phytochemical and synthetic studies of indole alkaloids having the Corynanthe-type related skeleton from genera Uncaria, Nauclea, and Mitragyna, which are classified under tribe Cinchoneae, family Rubiaceae, are described.

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Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 98%

Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 99%

Section: -2 Alkaloids In Uncaria Attenuatamentioning

confidence: 99%

Section: -1 Alkaloids In Uncaria Rhynchophyllamentioning

confidence: 99%

See 2 more Smart Citations

Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

Takayama¹,

Kitajima²,

Kogure

2005

COC

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“…[5] This quinolizidines ystemc onstitutes the core of the corynanthean alkaloids, with ap rominentc ongener termedg eissoschizine ( Figure 1). [1] Geissoschizine derivatives display structural variationsw ith regard to the C19ÀC20 double-bond geometry.…”

Section: Introductionmentioning

confidence: 99%

The Double‐Bond Configuration of Corynanthean Alkaloids and Its Impact on Monoterpenoid Indole Alkaloid Biosynthesis

Eckermann

Gaich

2016

Chemistry A European J

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Experimental evidence is provided for the coherence of the double-bond geometry and the occurrence of "secondary cyclizations" in the biosynthesis of monoterpenoid indole alkaloids. Biosynthetically, akuammiline, C-mavacurine, and Strychnos alkaloids are proposed to be derived from the corynanthean alkaloid geissoschizine, a key intermediate in the biosynthetic pathway of these monoterpenoid indole alkaloids. This process occurs by so-called "secondary cyclizations" from geissoschizine or its derivatives. Although corynanthean alkaloids like geissoschizine incorporate E or Z double bonds located at C19-C20, the alkaloids downstream in the biosynthesis exclusively exhibit the E double bond. This study shows that secondary cyclizations preferentially occur with the E isomer of geissoschizine or its derivatives. This is attributed to the flexibility of the quinolizidine system of the corynanthean alkaloids, which can adopt a cis or trans conformation. For the secondary cyclization to take place, the cis-quinolizidine conformation is required. Experimental evidence supports the hypothesis that the E double bond of geissoschizine induces the cis conformation, whereas the Z double bond induces the trans conformation, which prohibits secondary cyclization of the Z compounds.

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Alkaloids and Lignans from the Aerial Parts of Rauvolfia tetraphylla Inhibit NO Production in LPS‐activated RAW 264.7 Cells

Tung,

Dung,

Kiem

et al. 2024

Chemistry & Biodiversity

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Three previously undescribed compounds named rauvolphyllas A‐C (1‐3), along with thirteen known compounds, 18β‐hydroxy‐3‐epi‐α‐yohimbine (4), yohimbine (5), α‐yohimbine (6), 17‐epi‐α‐yohimbine (7), (E)‐vallesiachotamine (8), (Z)‐vallesiachotamine (9), 16S‐E‐isositsirikine (10), Nb–methylisoajimaline (11), Nb–methylajimaline (12), ajimaline (13), (+)‐lyoniresinol 3α‐O‐β‐D‐glucopyranoside (14), (+)‐isolarisiresinol 3α‐O‐β‐D‐glucopyranoside (15), and (‐)‐lyoniresinol 3α‐O‐β‐D‐glucopyranoside (16) were isolated from the aerial parts of Rauvolfiatetraphylla L. Their chemical structures were elucidated based on the extensive spectroscopic interpretation of HR‐ESI‐MS, 1D and 2D NMR spectra. The absolute configurations of 2 and 3 were determined by experimental ECD spectra. Compounds 5, 6, 7, and 11‐13 exhibited nitric oxide production inhibition activity in LPS‐activated RAW 264.7 cells with the IC50 values of 79.10, 44.34, 51.28, 33.54, 37.67, and 28.56 μM, respectively, compared to that of the positive control, dexamethasone, which showed IC50 value of 13.66 μM. The other isolates were inactive with IC50 values over 100 μM

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Conformational Study of Geissoschizine Isomers and Their Model Compounds

Cited by 15 publications

References 14 publications

Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

The Double‐Bond Configuration of Corynanthean Alkaloids and Its Impact on Monoterpenoid Indole Alkaloid Biosynthesis

Alkaloids and Lignans from the Aerial Parts of Rauvolfia tetraphylla Inhibit NO Production in LPS‐activated RAW 264.7 Cells

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