排序方式: 共有16条查询结果,搜索用时 31 毫秒
1.
2.
Rhea C. Garcellano John R. Cort Syed G. A. Moinuddin Scott G. Franzblau Rui Ma 《Natural product research》2020,34(8):1175-1179
AbstractCoronaridine (1) was isolated from the CH2Cl2 root extract of Tabernaemontana ternifolia. The structure of 1 was established from 1D- and 2D-NMR and HR-ESIMS experiments, and by comparison with reported spectroscopic data. To date, this is the first report of compound 1 from T. ternifolia, introduced as new Tabernaemontana species from Philippines in 2005 on the basis of morphological characters. Coronaridine, an iboga-type indole alkaloid, has been isolated from over 50 Tabernaemontana species and can thus be inferred as a chemotaxonomic marker of the genus. T. ternifolia has a distinct arrangement of leaves not known in the genus, but is variable in other genera. Its isolation from endemic T. ternifolia establishes its position in the genus and supports the claim that coronaridine is a chemical marker of the genus Tabernaemontana. Interestingly, coronaridine exhibited relatively weak activity against Mycobacterium tuberculosis H37Rv (MIC 82.64?μg/mL) (Rifampicin MIC 0.05?μg/mL). 相似文献
3.
The microwave spectrum of 3-hydroxytetrahydrofuran was recorded using a Fourier transform microwave spectrometer; the rotational constants (MHz) are: A = 5581.8230(7), B = 3638.8316(7), and C = 2924.7410(7). Microwave spectra for four (13)C isotopic species were recorded in natural abundance. Stark effect measurements were used to determine the projections of the dipole moment on the principal inertial axes: μ(a) = 0.956(1) D, μ(b) = 0.875(2) D, μ(c) = 1.050(2) D, and μ(tot) = 1.667(2) D. The internal coordinates of the carbon and oxygen atoms were least-squares fit to the 15 moments of inertia, and the best-fit structure is a C(4')-endo envelope ring conformation, in good agreement with ab initio calculations (MP2/6-31Gdaggerdagger). Copyright 2000 Academic Press. 相似文献
4.
5.
Min Tu Helge Reinsch Sabina Rodríguez‐Hermida Rhea Verbeke Timothe Stassin Werner Egger Marcel Dickmann Bjorn Dieu Johan Hofkens Ivo F. J. Vankelecom Norbert Stock Rob Ameloot 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2445-2449
Metal–organic frameworks (MOFs) enable the design of host–guest systems with specific properties. In this work, we show how the confinement of anthracene in a well‐chosen MOF host leads to reversible yellow‐to‐purple photoswitching of the fluorescence emission. This behavior has not been observed before for anthracene, either in pure form or adsorbed in other porous hosts. The photoresponse of the host–guest system is caused by the photodimerization of anthracene, which is greatly facilitated by the pore geometry, connectivity, and volume as well as the structural flexibility of the MOF host. The photoswitching behavior was used to fabricate photopatternable and erasable surfaces that, in combination with data encryption and decryption, hold promise in product authentication and secure communication applications. 相似文献
6.
The functional Ito formula, in the form df() = f( + d ) f(),is formulated and proved in the context of a Lie algebra L associatedwith a quantum (non-commutative) stochastic calculus. Here fis an element of the universal enveloping algebra U of L, andf() + d() f() is given a meaning using the coproductstructure of U even though the individual terms of this expressionhave no meaning. The Ito formula is equivalent to a chaoticexpansion formula for f() which is found explicitly. 1991 MathematicsSubject Classification: primary 81S25; secondary 60H05; tertiary18B25. 相似文献
7.
Bobeldijk I Bouwhuis M Ireland DG de Jager CW Jans E de Jonge N Kasdorp WJ Konijn J Lapikás L van Leeuwe JJ van der Meer RL Nooren GJ Passchier E Schroevers M van der Steenhoven G Steijger JJ Theunissen JA van Uden MA de Vries H de Vries R de Witt Huberts PK Blok HP van den Brink HB Dodge GE Harakeh MN Hesselink WH Kalantar-Nayestanaki N Pellegrino A Spaltro CM Templon JA Hicks RS Kelly JJ Marchand C 《Physical review letters》1994,73(20):2684-2687
8.
9.
Dr. Timothée Stassin Dr. Steve Waitschat Dr. Niclas Heidenreich Dr. Helge Reinsch Finn Pluschkell Dmitry Kravchenko João Marreiros Dr. Ivo Stassen Jonas van Dinter Rhea Verbeke Dr. Marcel Dickmann Dr. Werner Egger Prof. Dr. Ivo Vankelecom Prof. Dr. Dirk De Vos Prof. Dr. Rob Ameloot Prof. Dr. Norbert Stock 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(47):10841-10848
Energy-efficient indoors temperature and humidity control can be realised by using the reversible adsorption and desorption of water in porous materials. Stable microporous aluminium-based metal–organic frameworks (MOFs) present promising water sorption properties for this goal. The development of synthesis routes that make use of available and affordable building blocks and avoid the use of organic solvents is crucial to advance this field. In this work, two scalable synthesis routes under mild reaction conditions were developed for aluminium-based MOFs: (1) in aqueous solutions using a continuous-flow reactor and (2) through the vapour-assisted conversion of solid precursors. Fumaric acid, its methylated analogue mesaconic acid, as well as mixtures of the two were used as linkers to obtain polymorph materials with tuneable water sorption properties. The synthesis conditions determine the crystal structure and either the MIL-53 or MIL-68 type structure with square-grid or kagome-grid topology, respectively, is formed. Fine-tuning resulted in new MOF materials thus far inaccessible through conventional synthesis routes. Furthermore, by varying the linker ratio, the water sorption properties can be continuously adjusted while retaining the sigmoidal isotherm shape advantageous for heat transformation and room climatisation applications. 相似文献
10.
Chaturvedula VS Rhea J Milanowski D Mocek U Prakash I 《Natural product communications》2011,6(2):175-178
Two new new diterpene glycosides, 13-[(2-O-(6-O-beta-D-glucopyranosyl)-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-glucopyranosyl-3-O-beta-D-fructofuranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (2) were isolated from the leaves of Stevia rebaudiana, along with the known steviol glycosides stevioside, rebaudiosides A-F and dulcoside A. The structures of the two new compounds were established on the basis of extensive 2D NMR (COSY, HSQC, and HMBC), MS and chemical studies. 相似文献