Novel Bis(bibenzyl) and (Propylphenyl)bibenzyl Derivatives from Dendrobium nobile

Two novel compounds possessing a bis(bibenzyl) (see 1 ) and a (propylphenyl)bibenzyl skeleton (see 2 ) and eight known compounds were isolated from the stems of Dendrobium nobile Lindl . (Orchidaceae). Their structures were identified by spectroscopic analyses.     

新型N-甲基吲哚类衍生物的设计、合成及抗肿瘤活性研究

本文以吲哚骨架为起点,设计合成了5个含吲哚骨架的新型有机小分子(4a-4e),通过NMR,IR和MS对目标化合物进行了结构表征.采用MTS法测试了目标化合物对SMMC-7721,Hela,MCF-7和HepG2癌细胞的体外抗肿瘤活性.结果表明,部分化合物选择性地作用于一种细胞,显示出较强的抑制肿瘤细胞增殖的活性,值得进一步研究.     

Carexanes: prenyl stilbenoid derivatives from Carex distachya

Metabolites with a new molecular skeleton, named carexane, have been isolated from the leaves of Carex distachya. The structures have been determined on the basis of the spectroscopic characteristics of the compounds. Bidimensional NMR has furnished important data useful for the characterization and the stereochemistry of the molecules. The compounds have a tetracyclic skeleton derived from the coupling of the prenyl moiety on a stilbenoid structure.     

Two Novel Antioxidative Stilbene Tetramers from Parthenocissus laetevirens

Laetevirenols F ( 1 ) and G ( 2 ), two novel stilbene tetramers with an unprecedented skeleton, were isolated from Parthenocissus laetevirens. Their structures were elucidated by spectroscopic analysis, including 1D‐ and 2D‐NMR experiments, and their possible biogenetic pathway was discussed. In addition, both compounds were determined to be potent singlet‐oxygen quenchers by electron paramagnetic resonance (EPR) experiments, which highlights their potential pharmacological applications in singlet oxygen mediated diseases.     

Analysis of fungal cyclopentenone derivatives from Hygrophorus spp. by liquid chromatography/electrospray-tandem mass spectrometry

Fruitbodies of the genus Hygrophorus (Basidiomycetes) contain a series of anti-biologically active compounds. These substances named hygrophorones possess a cyclopentenone skeleton. LC/ESI-MS/MS presents a valuable tool for the identification of such compounds. The mass spectral behaviour of typical selected members of this group under positive and negative ion electrospray conditions is discussed. Using the ESI collision-induced dissociation (CID) mass spectra of the [M + H]+ and [M - H]- ions, respectively, the compounds can be classified with respect to the substitution pattern at the cyclopentenone ring and the type of oxygenation at C-6 (hydroxy/acetoxy or oxo function) of the side chain. The elemental composition of the fragment ions was determined by ESI-QqTOF measurements. Thus, in case of the negative ion CID mass spectra an unusual loss of CO2 from the deprotonated molecular ions could be observed.     

Studies on the complex formation between lactams and thiolactams of sparteine with copper(II) cation

The complex formation for lactams and thiolactams of sparteine with Cu(II) cation in ethanol was studied by theoretical, kinetic and MS methods. The studied compounds with Cu(II) cation formed 1:1 and 1:2 complexes. The kinetic parameters of their formation were determined. Both kinetic and thermodynamic parameters depend strongly on the presence of oxo- or thiono-group in sparteine skeleton.     

Searching for a new family of modified CL-20 cage derivatives with high energy and low sensitivity

A new family of energetic caged compounds was designed by introducing -NH- into the CL-20 skeleton and their energetic properties and impact sensitivity were investigated by using density functional theory. The results indicate that favorable substitution positions of the amine groups in the skeleton is helpful for increasing the heats of formation. Most of the seven compounds have high crystal densities above 1.9 g/cm³. Five compounds have the predominant detonation properties over CL-20. The derivatives with one NH₂ group have lower impact sensitivity than those with two NH₂ groups. Taking the detonation performance and impact sensitivity into consideration, four compounds may be selected as the potential candidates of high energy density compounds.     

手性螺-环丙烷类化合物的结构特征和解析

通过IR,¹HNMR,¹³CNMR,UV,MS以及X射线晶体衍射测定方法来确认一类新的手性螺-环丙烷化合物的化学结构.为研究新的螺环/环丙烷类复杂化合物的结构提供了有价值的依据.     

Non‐Alkaloidal Constituents from the Stem of Ficus Septica

Seven triterpenes, two lignans, and twelve other known compounds were isolated from the non‐alkaloidal fractions of the stem of Ficus septica Among these triterpenoids, a rare triterpene skeleton derivative, 13,27‐cycloursan‐3β‐ylacetate was isolated from natural sources for the first time. All the structures of these compounds were elucidated by spectroscopic methods.     

Polyoxygenated Klysimplexane- and Eunicellin-Based Diterpenoids from the Gorgonian Briareum violaceum

Three new polyoxygenated diterpenoids with a rare 4-isopropyl-1,5,8a-trimethylperhydrophenanthrane structure of the klysimplexane skeleton, briarols A‒C (1‒3), and one eunicellin-based diterpenoid, briarol D (4), were isolated from Briareum violaceum, a gorgonian inhabiting Taiwanese waters. The chemical structures of these compounds were determined by employing extensive analyses of NMR and high-resolution electrospray ionization mass spectrometry (HRESIMS) data. Metabolites 1‒3 were found to possess the rarely found skeleton of the diterpenoid klysimplexin T. All isolated compounds showed very weak cytotoxic activity against the growth of three cancer cell lines. A plausible biosynthetic pathway for briarols A‒C from the coexisting eunicellin diterpenoid briarol D (4) was postulated.     

含脱氢松香骨架的1,8-萘酰亚胺衍生物的合成及其对阴离子的识别

以歧化松香胺为原料合成了6个新型含脱氢松香骨架的1,8-萘酰亚胺衍生物2a～2b和3a～3d,其结构用1H NMR,13C NMR,MS和元素分析进行了表征.对3a～3d进行了阴离子识别研究,并对其识别机理进行了讨论.     

BI- and tricyclic diterpenoids from Halimium viscosum

The study of the acid and neutral parts of the n-hexane extract of Halimium viscosum (S. Jo?o da Pesqueira, Portugal) has led to the isolation of various known diterpenoids with the ent-halimane skeleton. Five new compounds have now been isolated, one with the ent-halimane skeleton, and four with the valparane skeleton, two of them with the valparane skeleton degraded. The structures of these compounds, determined by spectroscopic methods using 2D experiments (1H-13C, HMQC and HMBC), were dimethyl 1(10)-halimen-15,18-dioate, dimethyl 3,19-dinor-15-valparen-2,4-dioate, methyl 16-nor-2,3-secovalpara-3,15-dioxo-2-oate, 1,3,5,1 5-valparatetraene and 3R-4alpha-methoxy-15-valparen-2-one.     

Two New‐Skeleton Compounds from Sarcandra glabra

Two new‐skeleton compounds, sarcaboside A ( 1 ) together with its artifact sarcaboside B ( 2 ), were isolated from the whole plant of Sarcandra glabra. Their structures were elucidated on the basis of extensive spectroscopic analysis as well as HR‐ESI‐MSⁿ study.     

Neue cannabinoide—III : Die struktur des cannabicumaronons und analoger verbindungen

The so far unknown cannabicoumaronon (2) with a benzofuranskeleton and a butanone-sidechain was isolated from hassish extracts. Its structure was determined by transformation into cannabichromanone (1)by ozonolysis. In addition compounds containing the same skeleton were detected.     

银催化的环化反应合成异喹啉的研究进展

含有异喹啉骨架的化合物是一类很重要的含氮杂环化合物,广泛存在于具有生物活性的天然产物、有机材料、以及药物分子中。传统的合成异喹啉的方法需要苛刻的反应条件,因此使用温和,简单的方法构建这一骨架的化合物具有重要的现实意义。银类化合物具有路易斯酸特性能够催化活化三键,利用这一特点并使用含氮的亲核试剂进行分子内亲核加成活化的三键是合成异喹啉衍生物的重要方法。本文主要综述了以2-炔基苄亚胺、2-炔基苄基叠氮、2-炔基苯甲醛肟、2-炔基苯甲醛腙及其（2-（乙炔基）芳基）-1,2,3-三唑为反应物,在银催化条件下构建异喹啉环的研究进展,并对部分反应的机理进行了讨论。     

Substituent effects on heats of formation, group interactions, and detonation properties of polyazidocubanes

We have calculated the heats of formation (HOFs) for a series of polyazidocubanes by using the density functional theory (DFT), Hartree-Fock, and MP2 methods with 6-31G* basis set as well as semiempirical methods. The cubane skeleton was chosen for a reference compound, that is, the cubane skeleton was not broken in the process of designing isodesmic reactions. There exists group additivity for the HOF with respect to the azido group. The semiempirical AM1 method also produced reliable results for the HOFs of the title compounds, but the semiempirical MINDO3 did not. The relationship between HOFs and molecular structures was discussed. It was found that the HOF increases 330-360 kJ/mol for each additional number of the azido group being added to the cubane skeleton. The distance between azido groups slightly influences the values of HOFs. The interacting energies of neighbor azido groups in polyazidocubanes are in the range of 2.3 approximately 6.6 kJ/mol, which are so small and less related to the substituent numbers. The average interaction energy between nearest neighbor --N3 groups in the most stable conformer of octaazidocubane is 2.29 kJ/mol at the B3LYP/6-31G* level. The relative stability related to the number of azido groups of the title compounds was assessed based on the calculated HOFs, the energy gaps between the frontier orbitals, and the bond orders of the C--N3 and C--C bonds. The predicted detonation velocity of hepta- and octa-derivatives is over 9 km/s, and the detonation pressure of them is ca. 40 GPa or over.     

Kitungolides A, B, and C, new diterpenes from a soft coral of a new genus

Three novel compounds, designated kitungolides A (1), B (2), and C (3), were isolated from a soft coral of a new genus collected at Kitungamwe, Kenya. The three new compounds are of a unique heterotricyclic skeleton. The structures and relative stereochemistry of the compounds were elucidated by interpretation of MS, COSY, HMQC, HMBC, and NOESY experiments. [structure: see text]     

Subduction of coset representations

Summary Enumerations of compounds based on a parent skeleton with and without the influence of obligatory minimum valency (OMV) are reported. The effect of the OMV is formulated by assigning different weights to the respective orbits of the parent skeleton. This type of enumeration requires introduction of several new concepts that are derived from the subduction of coset representations, e.g., a unit subduced cycle index, a subduced cycle index and the number of suborbits.     

Synthesis of tricyclic compounds as steroid 5alpha-reductase inhibitors

A series of 4-phenoxybutyric acid derivatives attached to a tricyclic skeleton were prepared and evaluated as 5alpha-reductase inhibitors. Structure activity relationships for these compounds in terms of rat epididymis (type 2) 5alpha-reductase inhibitory activities reveal that 1) the substitution pattern at the 11-position of dibenz[b,e]oxepin influenced potency, 2) higher lipophilicity of the tricyclic skeleton improved potency, whereas the existence of a basic nitrogen atom in this skeleton was detrimental to potency, and 3) isobutyl substitution at the 8 positon of the azepine skeleton was tolerated. Among the tricyclic compounds studied, 4-[3-[5-benzyl-8-(2-methyl)propyl-10,11-dihydrodibenz[b,f]azepine- 2-carboxamido]phenoxy]butyric acid (26) was the most potent inhibitor of rat type 2 5alpha-reductase at 0.1 microM.     

Cytotoxic and novel skeleton compounds from the heartwood of Chamaecyparis obtusa var. formosana

The novel skeleton compounds, chamaecypanone C (3) and obtunorlignan A (4) were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structure of 3 was elucidated as a dimeric of monoterpene and norlignan with tricyclo[5.2.2.0^2.6]undecane and the structure of 4 was elucidated as a norlignan skeleton by spectroscopic methods. Compound 3 exhibits potent cytotoxic activity against several human cancer cells with IC₅₀ values ranging from 0.19 to 0.52 μM, whereas 4 has no activity.