A short synthesis of (±)-tecomanine via a Pauson-Khand-based route

The N-carboethoxy precursor to (±)-tecomanine has been prepared in 11 steps from 2-methyl-1-buten-3-yne. The key step, Pauson-Khand cyclization of a methylated 5-aza-6-nonen-1-yne succeeds, but only in low yield, a consequence of the dialkyl substitution about the azaenyne framework. Nevertheless, the overall sequence to that point is one of the more efficient to be described.     

The first total synthesis of (±)-annosqualine by means of oxidative enamide-phenol coupling: pronounced effect of phenoxide formation on the phenol oxidation mechanism

The first total synthesis of a spiro-isoquinoline alkaloid, (±)-annosqualine, was established by employing an enamide-phenol coupling of a 1-methylene-1,2,3,4-tetrahydroisoquinoline derivative with a hypervalent iodine reagent, where the formation of the phenoxide was recognized to be an essential step for the reaction of the phenolic hydroxyl group with the hypervalent iodine reagent leading to the formation of the desired product.     

A new Dendrobine-Type Alkaloid from Dendrobium nobile

A new dendrobine-type alkaloid has been isolated from stems of Dendrobium nobile lindl.Its structure has been identified on the basis of spectroscopic method.     

Saframycins 及Ecteinascidins化合物的合成研究进展

综述了两类双四氢异喹啉生物碱Saframycins和Ecteinascidins的合成研究进展. 分析了各合成路线的关键步骤, 部分讨论了各方法的优缺点, 并对其生物合成和作用机理作了简单介绍.     

THE FORMATION AND CRYSTAL STRUCTURE OF DIHYDRONITIDINE AND DISCUSSION OF ANTICANCER MECHANISM OF NITIDINE CATION

The paper reports the formation and crystal structure of dihydronitidine, expounds thereasons and conditions of easily formed oxynitidine, and discusses anticancer mechanism ofnitidine (cation). The crystallographic parameters of dihydronitidine are: space group P2_(1/n),a= 12.54(1), b = 9. 148(5), c = 14.748(8)A, β= 92. 12(6)°,Z =4. 4108 independent reflec-tions were collected within the range of 3°≤2θ≤54°, of which 2137 intensity data with I≥3σ(I) were used in the structural determination. The crystal structure has been refined byfull matrix least-square method to a final R of 0.050.     

Kottamide E, the first example of a natural product bearing the amino acid 4-amino-1,2-dithiolane-4-carboxylic acid (Adt)

Kottamide E, a novel alkaloid containing dibrominated indole enamide, oxalic acid diamide and 4-amino-1,2-dithiolane-4-carboxamide moieties, has been isolated from the New Zealand ascidian Pycnoclavella kottae. Characterisation was achieved by interpretation of spectroscopic data.     

两个特殊骨架的C_(20)－二萜生物碱的全部~1H(~(13)C)核磁共振信号指定

两个具有特殊骨架的C_(20)-二萜生物碱北乌灵（kusnezoline）和峨翠灵（ omeieline）分别分自中国特产毛茛科植物北草乌（Aconitum hkusnezoffii Paritz）、彭州岩乌头（A. racemulosum var. pengzhouense）和峨眉翠雀花（ Delphinium omeiense W. T. Wang）。应用2D NMR技术(~1H-~1H COSY, HMQC, HMBC, NOESY)全面归属了这两个生物碱的~1H和~(13)C信号的化学位移。     

弯距翠雀花中二萜生物碱的结构鉴定

从弯距翠雀花(Delphinium campylocentrum Maxim.)全草中分离得到7种二萜生物碱, 其中弯翠生(1)和弯翠亭(2)为两个新的C₁₉-二萜生物碱, 其余5个为已知的二萜生物碱. 化合物1和2的结构通过现代波谱技术, 包括二维核磁共振谱和高分辨质谱, 予以了确证.     

C19-二萜生物碱贡乌生的结构研究

毛茛科植物贡嘎乌头 ( Aconitum liljestrandii)具有镇痛、镇静、祛风湿等功效 ,产于我国西藏东部及四川西部 [1] .我们从其块根中分得 1 8个单体 ,其中 1 6个为已知生物碱 [2 ,3] ,2个为新生物碱 [3] .本文报道新的 C19-二萜生物碱贡乌生 ( Liljestrandisine) 1的结构 .1　实验部分1 .1　仪器与试剂　 Boetius微量熔点测定仪 ;Nicolet FTIR2 0 0 SXV型红外光谱仪 ,KBr压片 ;BrukerAC- E2 0 0和 Varian Unity INOVA40 0 /5 4核磁共振仪 ,溶剂为 CDCl3,TMS为内标 ;VG Autospec30 0 0型和 VG70 A型质谱仪 ;Pekin Polarimete…     

海绵Phacelliafusca中含氮化合物的分离与结构鉴定

从采自中国南海西沙群岛海域的海绵Phacellia fusca Schmidt中得到4个含氮 化合物。经~1H NMR,~(13)C NMR,HMQC,HMBC,~1H-~1HCOSY,FABMS和EIMS等光谱分析 ，确证其结构分别为：N,N'-二[2-乙氧基-1（Z）-乙烯基]脲（1），2- Bromoaldisin(2),Aldisin(3)Dibromophakellin盐酸盐(4)。其中化合物1为一具有 对称结构的新脲类化合物，命名Phacelliaurea A；化合物4是首次从该海绵中分离 得到的已知胍基生物碱，首次报到了它的~(13)C NMR数据及其归属。