A New Alkaloid from Patrinia scabra

Patrinia scabra Bunge is indigenous to the northeastern part of China. It has long been used as a traditional medicine for treating leukemia, cancer and for regulating host immune response. Some iridoids and iridoid glycosides have been found previously in this plant1, 2. We report here the isolation and structural elucidation of a new alkaloid, patriscabratine (1) from P. scabra. The EtOAC-soluble fraction from the ethanolic extraction of the air-dried roots of P. scabra was further fr…     

The Synthesis, Crystal Structure and Thermoanalysis of N-Salicylidene Glycine Tripyridine Nickel( Ⅱ )

Introduction Complexes of some Schiff bases with transition metals are widely used, for example, they can be used as anticancer medicine, preservative, complex reagent and the model of the biological oxygen carrier. So their syntheses, properties and application have been intensively studied. In order to study the relationship between the     

Construction and application of an electrochemical sensor based on graphene-MXene nanocomposites for baicalin detectionEI北大核心CSCD

Redox graphene-MXene(rGO-MXene) nanocomposites were prepared by ion polymerization and used to construct a highly sensitive electrochemical sensor for baicalin(BA) detection. The synergistic effect of rGO and MXene increased the specific surface area and electron transport capacity of the electrode, and significantly enhanced the electrochemical response of BA. The cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of BA on the sensor. Under the optimal conditions, the peak current exhibited a good linear relationship with BA concentration in the range of 0. 05-10 μmol / L, and the limit of detection was as low as 28 nmol / L. The method was applied to analyze traditional Chinese medicine preparations containing baicalin, such as Qingkailing Capsule and Sanhuang Tablets with good accuracy and spiked recovery. The results were highly consistent with those of high performance liquid chromatography, providing a technical means for the rapid and sensitive detection of traditional Chinese medicine preparations. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Total Synthesis of (±)-Celaphanol A

Celaphanol A was a diterpene isolated from the stems of Celastrus stephanotifolius1, which have been the subject of continued and growing interest, due to the range of biological activities shown by many members of this family2. Some have been used in traditional medicine3 or as a stimulant4 from ancient times. In order to further study the relationship between the structure and biological activity of the diterpene compound and as an extension of diterpenoid synthesis in our laboratory5, 6, …     

A New Eudesmanolide and a New Aromatic Derivative from Carpesium cernuun

Carpesium cernuun L. has long been used as chinese folk medicine for its anti-inflammatory, pain-relief, and detoxication properties1. Up to now, no phytochemical studies of Carpesium cernuun has been carried out. Here we report the structure elucidation of a new eudesmanolide 1 and a new aromatic derivative 2, which were obtained from this plant. Compound 1 was isolated as colorless gum, [(]+128.4 (c 0.43, CHCl3). Its EIMS revealed a molecular ion peak m/z 248. Together with the support …     

A New Flavone Glycoside from Epimedium koreanum

Epimedium koreanum is widely distributed throughout the east-northern part of China. As a Chinese herbal medicine, its aerial parts are used as tonics, aphrodisiacs and antirheumatics. Constituents of Epimedium koreanum have been reported as flavonoids, n…     

The first systhesis of a chromia-pillared layered niobate with porosity, acidity and high thermostability

Although the hydrated niobic acid is an unusual solid acid and making an impact onits application in catalysis, it is usually nonporous and has a rather low surface area andweak acidity upon heat treatment. To overcome these shortcomings, the layered nio-bate had been pillared with thermostable inorganic oxides such as alumina and silica.Chromia is also a suitable inorganic oxide which can be used as pillar and contributesnew properties to the resultant materials. Here, we report the first synthesis of achromia-pillared layered niobate with porosity, acidity and thermostability.     

Thermal Characterization and Decomposition Kinetics of Free Anthraquinones from Rhubarb

Rhubarb is an important Chinese traditional medicine and its genins such as aloe-emodin have been widely used in the field of antibacterial, antivirus, antitumor and antibacterial immunity1,2. Chrysophanol and physcion are the effective components for dec…     

Two New Bisabolane Sesquiterpenes from Leontopodium longifolium

Leontopodium longifolium (Compositae) have long been used as folk medicine in China for releasing a cough, expectorant and treatment of bronchitis1,2. The chemical constituents of the Leontopodium longifolium were not reported so far. Here we report the s…     

Two New C29 Sterols from Clerodendrum colebrookianum

Clerodendrum. colebrookianum Walp. is a traditional Chinese medicine, it possesses thefunctions of "expelling toxin by cooling, cooling blood to induce diuresis and purgingheat"', and has been used as a remedy for hypertension in india2. The chemicalinvestigation of this plant has been reported previously'-'. In continuation of our studieson the constituents of the plant, we examined the steroid constitllents of the title speciesand isolated two new C,, sterols, colebrin A (l) and colebrin B…     

Generalized P,Q and G conditions

The N-Representability Problem entails characterizing the set of second order reduced states that are contractions of N-electron states of the Fermion Fock algebra. This problem is formulated in the form of finding the conditions that a positive linear functional defined on a subspace of this algebra must satisfy in order to be extended to the whole algebra. As this algebra is a w*-algebra one can utilize a theorem by Kadison that shows it is sufficient to consider the values of linear functionals on projectors contained in the subspace in order to determine whether they have positive extensions. Thus we find the form of projectors belonging to the subspace of one and two particle operators and subsequently show that the extension conditions needed in the N-Representability Problem correspond to generalized P, Q and G conditions plus the additional constraints that the functionals be dispersion free on the number operator and their values on one particle operators determined by their values on two particle operators.     

Total Syntheses of Cyanthiwigins B,F, and G

A concise and versatile approach toward the preparation of the cyanthiwigin family of cyathane natural products is described. By leveraging a unique double asymmetric catalytic alkylation procedure it is possible to quickly establish two of the most critical stereocenters of the cyanthiwigin framework with high levels of selectivity and expediency. The synthetic route additionally employs both a tandem ring‐closing cross‐metathesis reaction, and an aldehyde‐olefin radical cyclization process, in order to rapidly arrive at the tricyclic cyathane core of the cyanthiwigin molecules. From this unifying intermediate, the preparations of cyanthiwigins B, F, and G are attained swiftly and without the need for protecting groups.     

Novel findings regarding photoinduced commitments of G1-, S- and G2-phase cells to cell-cycle transitions in darkness and dark-induced G1-, S- and G2-phase arrests in Euglena.

Effects of light and darkness on cell-cycle progression were studied in the log-linear photoautotrophic growth mode of Euglena gracilis. We found that there are light-dependent restriction points in the post-G1 phases, quite in contrast to Chlamydomonas, where a light-dependent restriction is known to exist only in the G1 phase. Thus, in E. gracilis, there are photoinduced commitments of G1-, S- and G2-phase cells that allow them to progress to the G1, S and G2 phases in darkness, and there are dark-induced G1-, S- and G2-phase arrests. In darkness, only committed cells were able to progress to the committed phases (G1, S or G2), whereas uncommitted cells were unable to undergo a cell-cycle transition. Whether or not cells were induced to commit by irradiation, they were eventually arrested somewhere in the G1, S or G2 (but not M) phase within 14 h of being transferred to darkness. We also describe the dependence of photoinduced commitment on light intensity and discuss the results as they relate to cell-cycle progression in continuous light.     

Total syntheses of the strobilurins G, M, and N

The key reactions in the general synthesis of strobilurins are the highly (Z)-selective Wittig reaction of an (E)-cinnamaldehyde with the phosphorus ylide 8 derived from (1,1-dibromoethyl)triphenylphosphonium bromide, followed by bromine-iodine exchange and Pd-Cu co-catalyzed Stille cross-coupling of the resulting alkenyl iodide with methyl (Z)-2-tributylstannyl-3-methoxyacrylate (7). The synthetic strobilurins G, M, and N were identical with the corresponding natural compounds. In addition, the (2′ S)-configuration of strobilurin G (1) was unambiguously established by oxidative degradation of the synthetic intermediate (S)-9 to (R)-2,3-dihydroxyisovaleric acid.     

Enantioselective total synthesis of eudistomidins G,H, and I

Asymmetric first total synthesis of eudistomidins G, H, and I, tetrahydro-β-carboline alkaloids from the Okinawan marine tunicate Eudistoma glaucus, has been accomplished with the Bischler–Napieralski reaction and the Noyori catalytic asymmetric hydrogen-transfer reaction. The absolute configurations of eudistomidins G, H, and I were confirmed from comparison of the ¹H and ¹³C NMR, and CD spectral data of synthetic and natural eudistomidins G, H, and I, respectively.     

Asymmetric total syntheses of (-)-jorumycin, (-)-renieramycin G, 3-epi-jorumycin, and 3-epi-renieramycin G

The total synthesis of (-)-jorumycin (1) and (-)-renieramycin G (2) has been accomplished in 25 and 23 steps, respectively, from 5-benzyloxy-2,4-dimethoxy-3-methyl-benzyl alcohol. The synthesis features a substrate-tunable stereoselective intramolecular Pictet-Spengler-type reaction for the construction of the key pentacyclic core of both targets, bearing either the natural configuration or the epimeric configuration at C-3. With access to a C-3 epi-pentacyclic framework, 3-epi-jorumycin (32) and 3-epi-renieramycin G (34) were also successfully synthesized. Furthermore, preliminary biological evaluation of 3-epi-jorumycin (32), in addition to relevant synthetic intermediates, revealed that significant cytotoxicity had been retained in these compounds. Therefore, these early studies constitute the basis for a new structure activity relationship (SAR) investigation for this class of antitumor antibiotics.