Angustimine and angustifolimine: two new alkaloids from Daphniphyllum angustifolium

Two new alkaloids, angustimine (1) featuring an unprecedented skeleton, and angustifolimine (2) being a rare diamino Daphniphyllum alkaloid, were isolated from Daphniphyllum angustifolium. Their structures were elucidated by extensive spectroscopic analysis. The biosynthetic origin of 1 was postulated. Cytotoxic activities of 1 and 2 were tested, and all of them were inactive.     

First diamino Daphniphyllum alkaloid, daphnipaxinin, with an unprecedented heterohexacyclic skeleton from Daphniphyllum paxianum

[structure: see text] The first diamino Daphniphyllum alkaloid, daphnipaxinin (1), with an unprecedented hexacyclic fused skeleton, along with a known alkaloid, daphnicyclidin A (2), was isolated from the stem of Daphniphyllum paxianum Rosenth. The structure and absolute stereochemistry of 1 were established by spectral methods, especially two-dimensional NMR techniques and CD analysis.     

Daphnicyclidins J and K, unique polycyclic alkaloids from Daphniphyllum humile

Two Daphniphyllum alkaloids with unprecedented polycyclic skeletons, daphnicyclidins J (1) and K (2), have been isolated from the stems of Daphniphyllum humile, and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 1 was established by chemical correlation with a known-related alkaloid, daphnicyclidin D (3), through a modified Polonovski reaction.     

Daphniglaucins A and B,novel polycyclic quaternary alkaloids from Daphniphyllum glaucescens

[structure: see text] Two cytotoxic quaternary Daphniphyllum alkaloids with an unprecedented fused-polycyclic skeleton containing a 1-azoniatetracyclo[5.2.2.0.(1,6)0.(4,9)]undecane ring system, daphniglaucins A (1) and B (2), have been isolated from the leaves of Daphniphyllum glaucescens. Their structures and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Calyciphylline D, a novel alkaloid with an unprecedented fused-pentacyclic skeleton from Daphniphyllum calycinum

[structure: see text]. Calyciphylline D (1), a novel Daphniphyllum alkaloid with an unprecedented fused-pentacyclic skeleton containing a 8-azatricyclo[4.2.1.0.4,8]nonane ring system, has been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Daphnicyclidins A-H, novel hexa- or pentacyclic alkaloids from two species of Daphniphyllum.

Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H (1-8), have been isolated from the stems of Daphniphyllum humile and D.teijsmanni, and their structures were elucidated on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data, and CD analyses.     

Daphmanidin A,a novel hexacyclic alkaloid from Daphniphyllum teijsmanii

A novel alkaloid with an unprecedented fused-hexacyclic skeleton, daphmanidin A (1), and a new pentacyclic alkaloid, daphmanidin B (2), have been isolated from the leaves of Daphniphyllum teijsmanii, and the structures were elucidated on the basis of spectroscopic data. The relative and absolute stereochemistry of 1 was determined by combination of NOESY correlations and a modified Mosher method.     

虎皮楠生物碱研究进展

虎皮楠生物碱结构多变且具有复杂的多环骨架, 该类生物碱奇特的多环结构使其成为化学和生物合成研究的热点之一. 最近的关于虎皮楠生物碱的综述是由Kobayashi和Morita等于2003年报道的, 文章对1987到2002年间虎皮楠生物碱的研究进行了概括. 其后又有从11种虎皮楠植物中分离到的60多个新的虎皮楠生物碱报道, 其中三分之二是由中国学者从分布于中国的虎皮楠植物中分离得到. 这些新生物碱有的骨架类型已知, 有的骨架新颖. 故对这些新生物碱的结构分类、可能的生物合成途径和生物活性进行了综述. 对生物碱的分类基本按照以前提出的方法, 但增加了7种新的骨架类型. 对各种骨架的结构特点及在生物合成中的相互关系也进行了讨论.     

Daphmanidins C and D, novel pentacyclic alkaloids from Daphniphyllum teijsmanii

[structure: see text] Two novel alkaloids with an unprecedented fused-pentacyclic skeleton, daphmanidins C (1) and D (2), have been isolated from the leaves of Daphniphyllum teijsmanii, and the structures were elucidated on the basis of spectroscopic data. The relative stereochemistry of 1 and 2 was assigned by combination of NOESY correlations and a simulation analysis. Daphmanidin C (1) elevated activity of NGF biosynthesis.     

Macropodumines A-C: novel pentacyclic alkaloids with an unusual skeleton or zwitterion moiety from Daphniphyllum macropodum Miq

Three novel alkaloids, macropodumines A-C (1-3), were isolated from the stem of Daphniphyllum macropodum Miq. Interestingly, the structure of macropodumine A (1) was characterized as having a fused pentacyclic system including an unusual eleven-membered macrolactone ring, whereas macropodumine B (2) contains a rare cyclopentadienyl carbanion, which is stabilized as a zwitterion by an internal iminium cation. The structures of these new metabolites were established on the basis of their detailed spectroscopic analysis. In particular, the unique structure of zwitterion 2 was further confirmed by using single-crystal X-ray diffraction analysis.     

A new phenol compound from endophytic Phomopsis sp. DC01

The strain DC01 was isolated from the branch tissue of Daphniphyllum longeracemosum and determined to be a member of Phomopsis according to the ITS sequence analysis. The extracts from the PDA solid fermentation media of Phomopsis sp. DC01 were purified and three compounds including one new phenol compound were obtained. The new compound was identified to be (E?)-7-(2-hydroxy-4-(hydroxymethyl)phenyl)-2-methyloct-6-enoic acid (1) based on 1-D NMR, 2-D NMR and HR-ESI data.     

Calyciphyllines A and B,two novel hexacyclic alkaloids from Daphniphyllum calycinum

[structure: see text] Two types of Daphniphyllum alkaloids with unprecedented fused-hexacyclic ring systems, calyciphyllines A (1) and B (2), have been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Paxdaphnidines A and B, novel penta- and tetracyclic alkaloids from Daphniphyllum paxianum

Two novel alkaloids, paxdaphnidine A (1) with a unique pentacyclic skeleton and paxdaphnidine B (2) with an uncommon tetracyclic skeleton, were isolated from the stems and leaves of Daphniphyllum paxianum. Their structures were established by spectral methods, especially two-dimensional NMR techniques ((1)H-(1)H COSY, HSQC, HMBC, and NOESY).     

Daphlongeranines A and B, two novel alkaloids possessing unprecedented skeletons from Daphniphyllum longeracemosum

Two novel alkaloids, daphlongeranines A (1) and B (2), with an unprecedented ring system, were isolated from the fruits of Daphniphyllum longeracemosum. Their unique structures and relative stereochemistries were established on the basis of spectroscopic and single-crystal diffraction analysis. The proposed biosynthetic pathway was also discussed. Compounds 1 and 2 showed weak inhibition on platelet aggregation.     

Two novel alkaloids with a unique fused hexacyclic skeleton from Daphniphyllum subverticillatum

Two novel major alkaloids, deoxycalyciphylline B (1) and deoxyisocalyciphylline B (2) with a unique fused hexacyclic skeleton, together with a quite recently reported alkaloid calyciphylline B (3), were isolated from the stem of Daphniphyllum subverticillatum. Their structures were established by spectral methods and chemical evidence, especially 2D NMR techniques. The structure of 1 was further confirmed by a single-crystal X-ray diffraction determination.     

Isolation, X-ray crystallography, and computational studies of calydaphninone, a new alkaloid from Daphniphyllum calycillum

[structure: see text]. A new hexacyclic alkaloid, calydaphninone (1), containing a 4-azatricyclo[5.2.2.0(1,4)]undecan ring system, has been isolated from the leaves and twigs of Daphniphyllum calycillum (Daphniphyllaceae). Its structure was elucidated by spectral and crystallographic means. Furthermore, conformations of calydaphninone (1) in solution are discussed on the basis of NMR spectral analysis and computational (B3LYP/6-31G*) results.     

Daphnilongerine, an unprecedented fused pentacyclic ring system alkaloid from Daphniphyllum longeracemosum Rosenth.

An unusual yuzurine-type alkaloid daphnilongerine (1), with an unprecedented fused pentacyclic skeleton in addition to seven known ones, daphnigracine (2), daphnezomine R, daphnigraciline, yuzurine, longistylumphyllines A, daphnilongeranin C, and calycinine A, was isolated from the fruits of Daphniphyllum longeracemosum. The structure and relative stereochemistry of 1 were determined by spectroscopic analysis.     

Calyciphylline G, a novel alkaloid with an unprecedented fused-hexacyclic skeleton from Daphniphyllum calycinum

Calyciphylline G (1), a novel Daphniphyllum alkaloid with an unprecedented fused-hexacyclic skeleton containing a 5-azatricyclo[6.2.1.0^1,5]undecane ring, has been isolated from the stem of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Cascade cyclization, dipolar cycloaddition to bridged tricyclic amines related to the Daphniphyllum alkaloids

A tandem one-pot reaction of an aldehyde with a primary amine involving condensation and then cyclization (N-alkylation), followed by intramolecular dipolar cycloaddition of the resulting nitrone or azomethine ylide, provides a synthesis of bridged tricyclic amines. The reaction was most successful using hydroxylamine, and when the dipolarophile was an unsaturated ester, subsequent reduction of the N-O bond and cyclization to the lactam provided the core ring system of the yuzurimine, daphnilactone B, and bukittinggine type Daphniphyllum alkaloids.     

卤代-2-(3-甲基-5-取代-4H-1,2,4-三唑-4-基)-苯甲酸的合成

邻氮基苯甲酸;缩合反应;卤代-2-(3-甲基-5-取代-4H-1;2;4-三唑-4-基)-苯甲酸的合成