One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Catalyzed by Chlorosulfonic Acid

An efficient synthesis of 3,4-dihydropyrimidin-2-ones (DHPMs) from the aldehydes, β-ketoesters and urea in ethanol using chlorosulfonic acid as the catalyst is described. Compared with the classical Biginelli reaction conditions, this method has the advantage of excellent yields and short reaction time

Chemo-, Regio-, and Stereoselective Assembly of Polysubstituted Furan-2(5H)-ones Enabled by Rh(III)-Catalyzed Domino C–H Alkenylation/Directing Group Migration/Lactonization: A Combined Experimental and Computational Study

Exploring multistep cascade reactions triggered by C–H activation are recognized as appealing, yet challenging. Herein, we disclose a Rh(III)-catalyzed domino C–H coupling of N-carbamoyl indoles and 4-hydroxy-2-alkynoates for the streamlined assembly of highly functionalized furan-2(5H)-ones in which the carbamoyl-directing group (DG) is given a dual role of an auxiliary group and a migrating acylating reagent via the cleavage of stable C–N bonds at room temperature. More importantly, the obtained furan-2(5H)-one skeleton could be further functionalized under air in situ via C5–H hydroxylation by simply switching the solvent or additive, providing fully substituted furan-2(5H)-ones with the installation of an alcohol-based C5 quaternary carbon center. Detailed experimental studies and density functional theory calculations reveal that a Rh(III)-mediated tandem C–H activation/alkyne insertion/DG migration/lactonization accounts for the developed transformation to achieve high functionalities with the observed exclusive selectivity. The potential biological application of the obtained furan-2(5H)-ones as a class of potent PPARγ ligands further highlights the synthetic utility of the developed methodology. This protocol is endowed with several salient features including efficient multistep cascade triggered by C–H activation, excellent chemo-, regio-, and stereoselectivity, high bond-forming efficiency (e.g., two C–C and two C–O bonds), solvent- or additive-controlled product selectivity, good functional-group compatibility, and mild redox-neutral conditions

TMRT observations of 26 pulsars at 8.6 GHz

Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities and pulse width parameters of these pulsars are estimated. For eleven pulsars these are the first high-frequency observations and for a further four, our observations have a better signal-to-noise ratio than previous observations. For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed profiles. A comparison of 19 profiles with those at other frequencies shows that in nine cases the separation between the outmost leading and trailing components decreases with frequency, roughly in agreement with radius-to-frequency mapping, whereas in the other ten the separation is nearly constant. Different spectral indices of profile components lead to the variation of integrated pulse profile shapes with frequency. In seven pulsars with multi-component profiles, the spectral indices of the central components are steeper than those of the outer components. For the 12 pulsars with multi-component profiles in the high-frequency sample, we estimate the core width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap

Immunosuppressive effect of voacamine from Voacanga africana Stapf based on SPRi experiment

Purpose: To investigate the affinity of a bis-indole alkaloid - voacamine from Voacanga Africana Stapf for IL-2Rα - and its immunosuppressive effect on concanavalin A-induced T cell proliferation and lipopolysaccharide -induced B cell proliferation in vitro. Methods: Surface plasmon resonance imaging (SPRi) was used to screen the target protein of voacamine, while CCK-8 kit was used to evaluate cytotoxicity. Mitogen-induced proliferation assay was carried out to assess the inhibitory effect of voacamine on Con A-induced T cell proliferation and LPSinduced B cell proliferation. The binding characteristics of voacamine were investigated using a binding model with IL-2Rα constructed based on molecular docking simulation. Results: Voacamine had a high-affinity for IL-2Rα with an equilibrium dissociation constant (KD) of 1.85×10-8 M. Cytotoxicity data showed that voacamine did not exhibit cytotoxicity at concentrations lower than 0.32 µM. However, it exerted significant immunosuppressive effect on B cells at a lower concentration, but had no influence on proliferation of T cells. Autodock results indicate that voacamine has a good interaction with the enzyme active site. Conclusion: Voacamine and its analogues exert influence on the immune system

Petrology, Physical Properties, and Diagenetic Characteristics of Glutenite Reservoir: An Example from the Upper Urho Formation in Zhongguai Salient, Junggar Basin, China

AbstractThe Upper Urho Formation on the northwest margin of the Junggar Basin is a key formation for oil and gas exploration. Based on the core observation, combined with the analysis of cast thin section, scanning electron microscope, energy dispersive spectrum, X-ray diffraction, fluid inclusion, and porosity-permeability test, the petrological characteristics, physical properties, diagenesis types, and their effects on the physical properties of the glutenite reservoir of Upper Urho Formation were studied systematically. The results show that the lithology of reservoir of the Upper Urho Formation in Zhongguai Salient is mainly conglomerate with a small amount of sandstone. The permeability of conglomerate is generally higher than that of sandstone, and the physical properties of granule conglomerate and fine pebble conglomerate are relatively better. The reservoir experienced complicated diagenesis, mainly including compaction, cementation, and dissolution, also including filler shrink seam and metasomatism. At present, the reservoir of Upper Urho Formation in Zhongguai Salient is mainly at the middle diagenetic stage A period and partly at the middle diagenetic stage B period. The original porosity lost by compaction is the largest, which is the fundamental reason for low porosity and low permeability of reservoir. The influence of cementation on reservoir physical properties has two sides. On the one hand, the development of cementation is the main reason for low porosity and low permeability of reservoir. On the other hand, the early cementation resists compaction to a certain extent and provides a material basis for the later dissolution. The reservoir of Upper Urho Formation in Zhongguai Salient is deeply buried and has experienced strong compaction and cementation, and the reservoir properties are poor, but the secondary pore space formed by dissolution improves the reservoir properties to some extent. The study concluded that the dense glutenite reservoirs of the Upper Urho Formation can develop relatively high-quality reservoirs on a local scale, which is of guiding significance for the exploration of the Upper Urho Formation