Search results for "Yield"
showing 10 items of 1338 documents
ChemInform Abstract: Synthesis of Elemane Bis-lactones from Santonin - Synthesis of the Reported Structure of seco-Isoerivanin Pseudo Acid and Formal…
2001
The synthesis of the reported structure for seco-isoerivanin pseudo acid (1) and of an elemane bis-lactone 5 from santonin (4) through a common vinylic precursor 12 is described. Compound 5 is a known intermediate in a previous synthesis of the antitumor compound (+)-8-deoxyvernolepin (3). The vinyl group of 12 underwent a regio- and diastereoselective anti addition of an external electrophile and an intramolecular condensation to yield either the selenolactone 13 or the hydroxylactone 17. The lactones 13 and 17 served as key intermediates in the total synthesis of 1 and 5 respectively. A revision of the structure of seco-isoerivanin pseudo acid to the C-10 epimer is suggested on the basis …
Synthesis, crystal and molecular structure of η3-allylundecacarbonylosmium tetrafluoroborate
1989
Abstract The η3-allylundecacarbonylosmium tetrafluoroborate has been synthesized in high yield by treatment of Os3(CO)11MeCN with allyl alcohol and subsequent protonation. It has been studied by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group Pna21 (no. 33) with a 17.933(2), b 11.440(2), c 11.797(2)A and Dc 2.76 g cm−3 for Z = 4. A final R value of 0.046 (Rw = 0.083) based on 2067 reflections was obtained. The presence of the positively charged allyl ligand in the triosmium cluster lengthens the Os1Os2 and Os2Os3 bonds (0.057A) and 0.074 A, respectively) relative to the OsOs bonds in Os3(CO)12.
Ent-clerodane diterpenoids from six further species of Teucrium
1985
Abstract Fifteen further species of the genus Teucrium have been investigated. Six of them contain known ent -clerodane diterpenoids; the others did not yield any diterpenoid. The chemotaxonomic significance of these results is discussed.
Following the Money: Revenue Stream Constituents in Case of Within-firm Variation
2014
The idea of this paper stems from the perception that the concept of revenue stream requires clarification and further division to be applicable to businesses with high internal variation in their methods of capturing revenue. Current study sets out to investigate the concept of revenue stream through an overview of previous literature and a case study to demonstrate how revenue streams of a b2b (business-to-business) software service firm can be analyzed by elaborating the concept further. The aim is to answer the following research questions: 1) What are the relevant constituents of the revenue stream concept within a b2b software services firm? 2) How revenue stream as part of the busine…
Atomistic Simulation of Transport Phenomena in Simple and Complex Fluids and Fluid Mixtures
2003
Computer simulations of fluids in thermal equilibrium can yield information on transport coefficients such as self—diffusion and interdiffusion coefficients, viscosity, and thermal conductivity. While the estimation of self—diffusion coefficients from the mean square displacements of the respective particles is rather straightforward, the estimation of other transport coefficients is less straightforward, and can be based on either an analysis of time correlation functions of the appropriate collective variables, or on nonequilibrium techniques where the linear response to appropriate perturbations is measured.
Size Distribution, Mechanical and Electrical Properties of CuO Nanowires Grown by Modified Thermal Oxidation Methods
2020
Size distribution, Young&rsquo
Bent-core liquid crystalline cyanostilbenes: fluorescence switching and thermochromism
2015
et al.
Long-term tillage and crop sequence effects on wheat grain yield and quality.
2013
Much research around the world has compared the performance of cereals grown under conventional and conservation tillage systems; however, relatively few long-term experiments have been conducted in Mediterranean areas, and little attention has been given to interactions among tillage techniques and other system components across space and time. In this study, we investigated the effects of the long-term (18-yr) use of three tillage techniques (conventional tillage, CT; reduced tillage, RT; and no-till, NT) on wheat (Triticum durum Desf.) grain yield and quality within three crop sequences: continuous wheat, faba bean (Vicia faba L.)–wheat, and berseem clover (Trifolium alexandrinum L.)–whe…
Micellar liquid chromatography in doping control.
2010
The issue of doping control in sport involves the development of reliable analytical procedures and efficient strategies to process a large number of samples in a short period of time. Reversed-phase LC techniques with aqueous–organic mobile phases and MS or diode-array detection yield satisfactory results for the identification of prohibited substances in sport. However, time-consuming sample pretreatment steps are required, which reduces sample throughput. Micellar LC (MLC) that uses hybrid mobile phases of surfactant above its critical micellar concentration and organic solvent has been revealed as an interesting alternative. The surfactant sodium dodecyl sulfate solubilizes the protein…
Dehydration of Fructose to 5-HMF over Acidic TiO2 Catalysts
2020
Different solid sulfonic titania-based catalysts were investigated for the hydrothermal dehydration of fructose to 5-hydroxymethylfurfural (5-HMF). The catalytic behavior of the materials was evaluated in terms of fructose conversion and selectivity to 5-HMF. The surface and structural properties of the catalysts were investigated by means of X-ray diffraction (XRD), N2 adsorption isotherms, thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and acid capacity measurements. Special attention was focused on the reaction conditions, both in terms of 5-HMF selectivity and the sustainability of the process, choosing water as the solvent. Among the various process condition…