天然产物的绝对构型研究(Ⅰ)——通过比较旋光和碳谱的实验值与计算值确定酮类、内酯类和醇类化合物的绝对构型

在研究天然产物绝对构型的过程中, 筛选了系列绝对构型未鉴定的化合物, 在B3LYP/aug-cc-pVDZ//B3LYP/6-31G(d)水平上计算了它们的旋光和碳谱数据. 结果表明, 计算结果与实验数值十分符合, 从而鉴定出了这些化合物的绝对构型. 另外, 根据计算结果和早期实验报告更正了1个化合物的碳谱化学位移.     

双丙炔醇酯类化合物的合成与表征

合成了5个新的二丙炔醇酯类化合物[(CO2CH2C≡CH)2(1),CH2(CO2CH2C≡CH)2,(2),(CH2CO2CH2C≡CH2)(3),(CHCO2CH2C≡CH)2,(4),C6H4-1,4-(CO2CH2C≡CH)2,(5)]，并对其进行了C／H，IR和^1H NMR等表征。     

Novel steroids from the seeds of Centratherum anthelminticum

Two novel and two known steroids were isolated respectively from benzene: acetone and ethanolic extracts of the seeds of C. anthelminticum and, identified as (24alpha/R)-Stigmasta-7-en-3-one (1), (24alpha/R)-Stigmasta-7, 9(11)-dien-3-one (2), (24alpha/S)-Stigmasta-5, 22-dien-3beta-ol (3) and (24alpha/S)-Stigmasta-7, 22-dien-3beta-ol (4). The structures were assigned on the basis of their IR, 1H NMR, 13C NMR (DEPT), 2D NMR (1H-1H COSY and 1H-13C COSY), mass spectra, chemical analyses and on comparison with literature values. The novel steroids (1) and (2) were also tested against several human pathogenic bacteria and fungi.     

Studies on the conformational flexibility of α-L-rhamnose-containing oligosaccharides using 13C-site-specific labeling, NMR spectroscopy and molecular simulations: implications for the three-dimensional structure of bacterial rhamnan polysaccharides

Bacterial polysaccharides are comprised of a variety of monosaccharides, L-rhamnose (6-deoxy-L-mannose) being one of them. This sugar is often part of α-(1 → 2)- and/or α-(1 → 3)-linkages and we have therefore studied the disaccharide α-L-Rhap-(1 → 2)-α-L-Rhap-OMe to obtain information on conformational preferences at this glycosidic linkage. The target disaccharide was synthesized with (13)C site-specific labeling at C1' and at C2', i.e., in the terminal group. 2D (1)H,(13)C-HSQC-HECADE and (1)H,(13)C-J-HMBC NMR experiments, 1D (13)C and (1)H NMR spectra together with total line-shape analysis were used to extract conformationally dependent hetero- and homonuclear spin-spin coupling constants. This resulted in the determination of (2)J(C2',H1'), (3)J(C1',C1), (3)J(C1',C3), (3)J(C2',C2), (2)J(C1',C2), (1)J(C1',C2'), and (1)J(C1',H1'). These data together with previously determined J(CH) and (1)H,(1)H NOEs result in fourteen conformationally dependent NMR parameters that are available for analysis of glycosidic linkage flexibility and conformational preferences. A 100 ns molecular dynamics (MD) simulation of the disaccharide with explicit water molecules as solvent showed a major conformational state at φ(H)≈ 40° and ψ(H)≈-35°, consistent with experimental NMR data. In addition, MD simulations were carried out also for α-L-Rhap-(1 → 3)-α-L-Rhap-OMe and a rhamnan hexasaccharide. The gathered information on the oligosaccharides was used to address conformational preferences for a larger structure, a 2- and 3-linked nonasaccharide, with implications for the 3D structure of rhamnan polysaccharides, which should be regarded as flexible polymers.     

Tris(pyronato)- and tris(pyridonato)-ruthenium(III) complexes and solution NMR studies

The water-soluble Ru(III) maltolato, ethylmaltolato, and pyridonato complexes, Ru(O-O')3 (O-O' = ma (1a), etma (1b), pyd (2a)), were synthesized (Hma = 3-hydroxy-2-methyl-4-pyrone, Hetma = 2-ethyl-3-hydroxy-4-pyrone, Hpyd = 3-hydroxy-1,2-dimethyl-4-pyridone). The complexes were characterized by elemental analysis, NMR and IR spectroscopies, MS, solution conductivity, and cyclic voltammetry, and in the case of Ru(ma)(3), by X-ray crystallography, which revealed a mer configuration. The paramagnetic 1H NMR resonances of 1a, 1b, and 2a were assigned using 2D methods (1H COSY and 1H-13C HMQC) and variable-temperature 1H NMR data and showed that 1a and 1b exist in aqueous solution predominantly as a mer isomer, while 2a is a mixture of mer and fac isomers. Although a 13C NMR spectrum could not be measured directly for 1a, a partial (13)C spectrum was generated from the 1H-13C HMQC spectrum. Complexes 1a and 1b were tested for anti-proliferatory activity against the human breast cancer cell line MDA-MB-435S and gave IC50 values of 140 and 90 microM, respectively.     

Complete assignments of 1H and 13C NMR data for seven arylnaphthalide lignans from Justicia procumbens

Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.     

闭苞买麻藤中的芪类化合物

对闭苞买麻藤植物进行了系统的化学成分研究，从65%的乙醇提取部分得到了 6介二苯乙烯单体化合物，分别为闭苞素D (1)，闭苞素E(2),丹叶大黄素(3),异丹 叶大黄素(4),4-甲氧基白藜芦醇(5)和银松素(6)，通过光谱方法（包括EI-MS,UV, IR,~1H NMR,~13C NMR和NOE）确定了它们的结构，其中，闭苞素D(1)，闭苞素E(2) 为两个新的二苯乙烯单体化合物。     

Structural and variable-temperature NMR studies of 9-diisopropylphosphanylanthracenes and 9,10-bis(diisopropylphosphanyl)anthracenes and their oxidation products

The diisopropylphosphanyl-substituted anthracenes i-Pr2P(C14H9) (1a), i-Pr2P(C14H8)Br (2a), and (i-Pr2P)2(C14H8) (3a) and some of their oxidation products were prepared from 9-bromoanthracene and 9,10-dibromoanthracene, respectively. Low-temperature (1)H NMR spectra of the 9-monophosphanyl-substituted anthracenes 1a and 2a are in accordance with a staggered conformer, while above room temperature dynamic processes occur. The low-temperature NMR spectrum of the 9,10-diphosphanylanthracene 3a indicates the presence of two different rotational isomers. The rotational barrier for 1a was determined from variable-temperature (1)H NMR spectra to be 56 kJ mol(-1) (DeltaG(298K)). The crystal structure determinations show the solid-state conformers to be consistent with the prevailing conformer at low temperature.     

Three new biflavonoids from Chinese dragon's blood, Dracaena cochinchinensis

Three new biflavonoids, named (2RyS)-3'-methoxy-8-methylsocotrin-4'-ol (1), (2SyR)-3'-methoxy-8-methylsocotrin-4'-ol (2), and (2RyR)-8-methylsocotrin-4'-ol (3), were isolated from Chinese Dragon's blood [Dracaena cochinchinensis (Lour.) S. C. Chen], together with two known ones. The structures of these new biflavonoids were elucidated by a combination of HR-ESI-MS, 1H NMR, 13C NMR, HMQC, and HMBC spectra. The absolute configurations of compounds 1-4 were determined by quantum chemical calculation of the circular dichroism spectrum and comparison with the experimental CD spectrum.     

Derivatization of fullerene dimer C120 by the Bingel reaction and a 3He NMR study of 3He@C120 monoadducts.

Cyclopropanation with diethyl bromomalonate and base (the Bingel reaction) was conducted on fullerene dimer C120 to give a mixture of "monoadducts" (45% yield) and "bisadducts" (< or =37% yield), while 18% of the C120 remained unchanged. The "monoadducts" were separated into five positional isomers, i.e., e(face), e(edge), trans-4, trans-3, and trans-2, by preparative HPLC. Assignments were made based on 1H (and 13C) NMR and confirmed by theoretical calculations of the addends' 1H NMR chemical shifts. The relative yields of these isomers were in fair agreement with those observed for the Bingel bisaddition of C60. The Bingel reaction was also carried out on the dimer C120 encapsulating 3He in one of the C60 cages. Each positional isomer of the "monoadduct" exhibited a pair of 3He NMR signals corresponding to an isomer with functionalization on the 3He-containing cage and the other isomer with functionalization on the empty cage. Using the 3He NMR spectroscopy, a pair of signals for the trans-1 isomer, which eluded detection by 1H NMR, were observed, in addition to pairs of signals for e(face), e(edge), trans-4, trans-3, and trans-2 isomers. The 3He NMR signals for isomers with functionalization on the 3He-containing cage were spread out over a 1.82-ppm range reflecting the direct effects of the addition pattern on the C60 surface. In contrast, the isomers with functionalization on the empty cage exhibited 3He NMR signals that appeared over a 0.14-ppm range, which was shown to be primarily due to changes in the diamagnetism of the functionalized cage based on theoretical calculations of 3He NMR chemical shifts for the model system in which the C60 cage encapsulating 3He was removed.     

Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.     

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。     

三对节中两个新环烯醚萜甙的研究

从三对节的叶子中分离得到４个化合物,经化学和光谱方法鉴定其为７－Ｏ－ｐ－Ｃｏｕｍａｒｏｙｌｏｘｙｕｇａｎｄｏｓｉｄｅ（１）,７－Ｏ－ｃｉｎｎａｍｏｙｌｏｘｙｕｇａｎｄｏｓｉｄｅ（２）,ａｃｔｅｏｓｉｄｅ（３）和ｍａｒｔｙｎｏｓｉｄｅ（４）,其中前两者是新环烯醚萜甙化合物,后两者为首次从该植物中获得的苯丙素甙类化合物。     

New C_(19)-Diterpenoid Alkaloids from the Roots of Delphinium

Three new C_(19)-diterpenoid alkaloids, giraldines A (1), B (3)and C (4), were isolated from the roots of Delphinium giraldiiDiels, together with three known C_(19)-diterpenoid alkaloids, di-hydrogadesine (5), tatsiensine (6) and siwanine A (7), as wellas their structures were elucidated by chemical evidence andspectral analyses, including IR, MS, 1D NMR and 2D NMR.     

直缘乌头中新的C19—二萜生物碱的结构研究

从直缘乌头（Aconitum transsectum Diels.）根中分离得到4个新的乌头碱型 C_(19)-二萜生物碱。由光谱法（IR, ~1H NMR, ~(13)C NMR, 2D-NMR, MS）确定其 结构为:8-O-乙基滇乌碱（8-O-ethylyunaconitine） (1)、去氮乙基查斯曼宁（N- deethyl chasmanine）(2)、直缘乌碱丁（transconitine D）(3)和直缘乌碱戊（ transconitine E）(4)。     

Structural determination of 3beta-stearyloxy-urs-12-ene from Maytenus salicifolia by 1D and 2D NMR and quantitative 13C NMR spectroscopy

Six pentacyclic triterpenoids, 3beta-stearyloxy-urs-12-ene (1), friedelin (2), 3beta-friedelinol (3), alpha-amyrin (4), beta-amyrin (5), and lupeol (6), have been isolated from the hexane extract of Maytenus salicifolia Reissek (Celastraceae) leaves. The molecular and structural formula as well as the stereochemistry of a new pentacyclic triterpene (1) were determined using data obtained from 1H and 13C NMR spectra, DEPT135 and by 2D HSQC, HMBC, COSY and NOESY experiments. The molecular formula C48H84O2 was established using quantitative 13C NMR, and the molecular weight (692 Da) was confirmed by elemental analysis and mass spectrometry (GC-MS).     

含穴醚N8O3配体的金属大环化合物的NMR研究

在溶液中,室温下对含有穴醚Ｎ８Ｏ３配体（Ｈ３Ｌ）的金属大环化合物［Ｎａ（Ｈ３Ｌ）］（ＣｌＯ４）３Ｈ２Ｏ（２）和［Ｌａ（Ｈ３Ｌ）（ＯＨ）２］（ＣｌＯ４）３（３）,作了１ＨＮＭＲ谱的测定,在化合物（２）－乙腈溶液中加入过量Ｌａ（ＣｌＯ４）３后的（２＋Ｌａ）和化合物（３）还作了１３Ｃ和１Ｈ－１ＨＣＯＳＹ（氢－氢相关二维谱）、１Ｈ－１３ＣＨＭＱＣ（氢核检测的异核多量子相干相关谱）及１Ｈ－１３ＣＨＭＢＣ（氢核检测的异核多键相关谱）的ＮＭＲ谱测定,归属了所有１Ｈ,１３Ｃ的谱线。对其配位行为通过１ＨＮＭＲ试验作了简单的讨论。     

Halogenated secondary metabolites from Laurencia obtusa

A new sesquiterpene (1), and a halogenated C15 acetogenin (2), a stereoisomer of neoisoprelaurefucin were isolated from Laurencia obtusa. Four known compounds laurencienyne (3), rogiolenyne B (4), obtusenol (5), and (3E)-dactomelyne (6) were also isolated from this alga. Rogiolenyne B (4) and (3E)-dactomelyne (6) were found for the first from this species. The structures of these compounds were elucidated by spectroscopic methods. The unambiguous assignments of the 1H and 13C NMR spectral data of (5) and 13C NMR data of (6) were also reported for the first time.     

含手性膦配体2-MBPA铂(Ⅱ)配合物的2DNMR

利用一维和二维ＮＭＲ技术,对含有手性膦配体的铂配合物ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡＨ）２Ｃｌ２〕（１）,ｔｒａｎｓ－〔Ｐｔ（２－ＭＢＰＡＨ）２Ｃｌ２〕（２）,ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡ）２〕（３）和ｃｉｓ－〔Ｐｔ（２－ＭＢＰＡ）（２－ＭＢＰＡＨ）Ｃｌ〕（４）进行１Ｈ和１３ＣＮＭＲ谱分析,区分了化合物（３）和（４）,归属了糖苷部分的１Ｈ和１３ＣＮＭＲ谱线,并根据磷和铂及磷与磷的偶合常数确定化合物（３）和（４）是顺式构型     

Complete assignments of 1H and 13C NMR spectral data for three sesquiterpenoids from Inula helenium

The complete assignments of all the (1)H and (13)C NMR signals of three sesquiterpene lactones, 4-oxo-5(6),11-eudesmadiene-8,12-olide (1), 4-oxo-11-eudesmaene-8,12-olide (2) and (1(10)E)-5beta-Hydroxygermacra-1(10),4(15),11-trien-8, 12-olide (3), were carried out by various 2D NMR experiments. Compounds 1-3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor-sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The (13)C-NMR data of compound 3 was also reported for the first time.