大渡乌碱的结构

从大渡乌头的根中分得一新的微量生物碱——大渡乌碱,其结构经化学方法及IR、~1HNMR、~13C NMR和MS推定为1.     

New C19-diterpenoid alkaloids from Aconitum piepunense

Two new C(19)-diterpenoid alkaloids, piepunensine A (1) and 18-acetylcammaconine (2), have been isolated from the roots of Aconitum piepunense together with five known alkaloids pengshenine B (3), talatisamine (4), aconosine (5), yunaconitine (6), and talatizidine (7). The structures of the new alkaloids were established on the basis of spectral data (1D- and 2D-NMR, HR-MS).     

A new diterpenoid alkaloid from Aconitum hemsleyanum

Abstract

A new C₁₉-diterpenoid alkaloid named hemsleyaline (1), along with fourteen known alkaloids (2-15), were isolated from the roots of Aconitum hemsleyanum Pritz. (Ranunculaceae), a herbal medicine in southwest China. Their structures were established on the basis of extensive spectroscopic analyses. Compound 1 showed mild cholinesterase inhibitory effect with IC₅₀ value of 471?±?9?μM.     

Unusual reactions of a 7,17-seco-type C19-diterpenoid alkaloid derived from deltaline

Treatment of a 7,17-seco-type C19-diterpenoid alkaloid (3), prepared from deltaline (8), with triethylamine in either DMF or TEG (triethylene glycol) at 120 degrees C provided two interesting compounds 6 and 7. The structures of compounds 3, 6, and 7 were established based on extensive interpretations of their 1D and 2D NMR data. Compound 6, a lycoctonine-type C19-diterpenoid alkaloid, can be transformed from alkaloid 3 via Grob fragmentation, Prins reaction, and intramolecular disproportionation. The mechanism of the formation of compound 6 was confirmed by deuteration experiments. Product 7 was formed through a pinacol-like rearrangement of alkaloid 3.     

New C19-diterpenoid alkaloids from the parent roots of Aconitum carmichaelii

Aconitum carmichaelii is a widely used traditional Chinese medicine and important source of clinical drugs. The parent roots of A. carmichaelii were investigated resulting in the isolation and identification of five new C₁₉-diterpenoid alkaloids; 14α-benzoyloxy-N-ethyl-15α-hydroxy-1α,6α,8β,16β,18-pentamethoxyaconitane formate (1), 14α-benzoyloxy-8β-butoxy-N-ethyl-13β,15α-dihydroxy-1α,6α,16β,18-tetramethoxyaconitane formate (2), 14α-benzoyloxy-8β-butoxy-N-ethyl-3α,13β,15α-trihydroxy-1α,6α,16β,18-tetramethoxylaconitane (3), 14α-benzoyloxy-8β-butoxy-3α,13β,15α-trihydroxy-1α,6α,16β,18-tetramethoxyl-N-methylaconitane (4) and 8β,14α-dibenzoyloxy-N-ethyl-13β,15α-dihydroxy-1α,6α,16β,18-tetramethoxyaconitane (5).     

Two new C19-diterpenoid alkaloids from Aconitum hemsleyanium var. circinacum

Two new C19-diterpenoid alkaloids, circinadines A (1) and B (2), were isolated from the roots of Aconitum hemsleyanium var. circinacum. Their structures were elucidated by chemical evidence and spectral analyses, including ESI-MS, HR-EI-MS, 1D- and 2D-NMR.     

Two novel aconane-type diterpenes derived from C-nor-C_(19)-diterpenoid alkaloid

Two novel C-nor-B-homo aconane-type diterpenes 4 and 5.featuring a unique eight-membered ring system,were obtained by the treatment of C-nor-C19-diterpenoid alkaloid 3 with HNO2 in 8%and 21%yields,respectively.Structures of these two compounds were established based on the combination of spectroscopic data,including HRESIMS,1D and 2D NMR data.A plausible mechanism for the formation of 4 and 5 is also presented.     

Five New C19‐Diterpenoid Alkaloids from Aconitum hemsleyanum

Five new C₁₉‐diterpenoid alkaloids, named hemsleyaconitines A–E ( 1 – 5 , resp.), were isolated from Aconitum hemsleyanum Pritz. By UV, IR, MS, 1D‐ and 2D‐NMR analyses, their structures were elucidated as 18‐dehydroxygeniculatine D ( 1 ), 6‐hydroxy‐14‐O‐veratroylneoline ( 2 ), 14‐O‐acetyl‐8‐ethoxysachaconitine ( 3 ), 18‐veratroylkaracoline ( 4 ) and 8‐O‐ethylaustroconitine B ( 5 ).     

Two new C_(19)-diterpenoid alkaloids from roots Aconitum hemsleyanium var. atropurpureum

A new franchetine-type C19-diterpenoid alkaloid 3-hydroxyfranchetine 1 and a new aconitine-type C19-diterpenoid alkaloid atropurpursine 2 have been isolated from the roots of Aconitum hemsleyanium var. atropurpureum. The structures of these new alkaloids were established on the basis of spectral data.     

Two novel skeletal rearrangements involving in the C ring of C19-diterpenoid alkaloid deltaline derivatives

Treatment of compounds 2 and 5, both from the C19-diterpenoid alkaloid deltaline 1, with 5% NaOH methanol (room temperature, 16 h) and NaOH-N,N-dimethylformamide (reflux, 10 h) led to the two novel skeletal rearrangement products 4 (90%) and 6 (62%), respectively, involving Wagner-Meerwein rearrangement and Grob fragmentation. Their structures were fully characteristized based on 2D NMR and HR-MS data.     

A new denudatine type C20-diterpenoid alkaloid from Aconitum sinchiangense W. T. Wang

A new denudatine-type C₂₀-diterpenoid alkaloid, designated as sinchianine (1), together with eight known diterpenoid alkaloids, 12-acetyl-12-epi-napelline (2), 12-epi-napelline (3), neoline (4), talatisamine (5), 14-O-acetylsenbusine A (6) and benzoylaconine (7), songorine (8) and aconitine (9), were isolated from the whole herb of Aconitum sinchiangense W. T. Wang. Their structures were elucidated on the basis of extensive spectroscopic analyses (NMR and HR-ESI-MS) and comparison with data reported in the literature.     

Two unique C21-diterpenoid alkaloids from Aconitum carmichaelii

Two sulfonated diterpenoid alkaloids possessing different but related novel carbon skeletons, named aconidenusulfonine A (1) and 12,16-secoaconidenusulfonine A (2), respectively, were isolated as minor components from an aqueous extract of the lateral roots of Aconitum carmichaelii (“Fu Zi”). The structures of 1 and 2, representing the first two C₂₁-diterpenoid alkaloids from nature, were determined by analysis of various spectroscopic data and chemical transformation, of which 1 was further proved by single-crystal X-ray diffraction. Especially, 1 exhibited dose-depended analgesic activity consistent with the clinical function of Fu Zi.     

Three New C19‐Diterpenoid Alkaloids from Aconitum hemsleyanum var. circinatum

Further phytochemical investigation of the roots of Aconitum hemsleyanum var. circinatum resulted in the isolation of three new aconitine‐type C₁₉‐diterpenoid alkaloids, hemsleyanines E–G ( 1 – 3 , resp.). The structures of these new alkaloids were elucidated on the basis of spectral data including 2D‐NMR.     

Hemsleyaconitines F and G,Two Novel C19‐Diterpenoid Alkaloids Possessing a Unique Skeleton from Aconitum hemsleyanum

Hemsleyaconitines F and G ( 1 and 2 , resp.) were isolated from the EtOH extract of Aconitum hemsleyanum. Their structures were elucidated by extensive analyses of the IR, 1D‐ and 2D‐NMR, and MS data. The two C₁₉‐diterpenoid alkaloids 1 and 2 possess a novel skeleton, featuring a five‐membered D‐ring between C(9), C(13), C(14), C(15), and C(16), which is quite different from the previously isolated six‐membered D‐ring analogs.     

Two novel C18-diterpenoid alkaloids,sinomontadine with an unprecedented seven-membered ring A and chloride-containing sinomontanine N from Aconitum sinomontanum

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New C19-diterpenoid alkaloids from Delphinium trifoliolatum

Three new norditerpenoid alkaloids, trifoliolasines A (1), B (3), and C (5), were isolated from the whole plant of Delphinium trifoliolatum FINET et GAGNEP, and their structures were established based on the spectral data.     

Three new C19-diterpenoid alkaloids from Delphinium giraldii

Further investigation of the roots of Delphinium giraldii DIELS led to the isolation of three new C(19)-diterpenoid alkaloids, giraldines G (1), H (2), and I (3). The structures of 1-3 were established based on spectroscopic evidence.     

Puberunine and puberudine, two new C18-diterpenoid alkaloids from Aconitum barbatum var. puberulum

Two C(18)-diterpenoid alkaloids, puberunine (1) and puberudine (2), together with four other new alkaloids, including the first examples having β-oriented substitution at C-3 and a rare chloro-substituent were isolated from Aconitum barbatum var. puberulum. Their structures were elucidated by spectroscopic methods. Puberunine and puberudine, which possess a unique rearranged E ring and an opened A ring, respectively, represent new subtypes of the C(18)-diterpenoid alkaloids. A plausible biosynthetic pathway of 1 and 2 was proposed.     

A new C<Subscript>19</Subscript>-diterpenoid alkaloid,habaenine C,from <Emphasis Type="Italic">Aconitum habaense</Emphasis>

A new C₁₉-diterpenoid alkaloid, habaenine C (1), together with the two known compounds vilmorrianine C and crassicauline A, were isolated from Aconitum habaense. The structure of the new compound was elucidated on the basis of spectral analysis, including 2D NMR spectroscopy. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 265–266, May–June, 2008.     

Three new C_(19)-diterpenoid alkaloids from Delphinium laxicymosum var. pilostachyum

Three new lycoctonine-type C19-diterpenoid alkaloids, laxicymine 1, laxicymisine 2, and laxicyminine 3 have been isolated from the whole herb of Delphinium laxicymosum var. pilostachyum W.T. Wang. Their structures were established by spectra data.