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2‐(chalcogen)benzothiazoles are frequently used as core structures for the development of pharmaceutical agents. A strategy for the synthesis of 2‐(chalcogen)benzothiazoles under electrooxidative conditions using isocyanides, thiols or diselenides as substrates was developed. This protocol allows access to structurally diverse 2‐(chalcogen)benzothiazoles in good yields and with good functional group tolerance, which does not require heavy metal catalysts and exogenous oxidants. Furthermore, gram‐scale synthesis was performed to demonstrate the scale‐up applicability of this reaction. [ABSTRACT FROM AUTHOR]

In order to study the characteristics and evolution for water inrush catastrophe of concealed collapse column of floor under mining, a concealed collapse column project was taken as the background. The process of water inrush catastrophe of concealed collapse column under different driving distances of working face was reproduced by considering fluid-solid coupling effect and dynamic change characteristics of surrounding rock permeability coefficient. On this basis, the influence of development height and water pressure of concealed collapse column on coal floor water inrush was studied. The research results show that: when the working face is excavated through the collapse column, the water-conducting fissure channel between the collapse column and the coal seam starts at the front of the top of the collapse column and ends at a position about 20 m from the coal seam floor to the center of the collapse column. With the excavation advancement of working face, the water inflow of coal floor is generally distributed in an “S” curve, which increases fastest when the working face is close to and passes through the collapse column, and gradually stabilizes after the working face is 35 m away from the center of collapse column. The closer the collapse column is to the coal bottom, the faster the time point at which water inflow of coal seam floor increases rapidly and the greater the range of its growth interval. At the same time, the amount of coal floor water inflow is exponentially decayed with the distance from collapse column top. When the driving distance of working face is same, the water inflow of coal floor has an exponentially increasing relationship with the water pressure of collapse column.

As a part of our systematic study on Castanopsis genus (Fagaceae), one new triterpene hydrolysable tannin (1) and two new phenol glucosides (2 and 3) were isolated from the leaves of Castanopsis eyrei (Champ. ex Benth.) Hutch. Compound 1 was identified as a triterpene hexahydroxydiphenoyl (HHDP) ester. This type of compounds has only been isolated from Castanopsis genus. The structures of 1-3 were elucidated by the combination of spectroscopic analysis (MS, 1 D and 2 D NMR) and chemical evidence. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the Leaves of Castanopsis eyrei led to the isolation of two new natural truxinate derivatives and a new phenyldilactone. The structures of the new natural compounds were determined by spectroscopic methods and chemical evidence as 3,3',4,4'-tetrahydroxy-β-truxillic acid (1), 3,3',4,4'-tetrahydroxy-δ-truxillic acid (2), 3'-hydroxymaysedilactone A (3). Establishment of a Caenorhabditis elegans lipid metabolism model using GFP and mCherry fluorescently labeled lipid droplets to screen compound 3 for its activity in reducing lipid accumulation. [ABSTRACT FROM AUTHOR]

Two new isoflavone compounds, Dalhancei A (1) and Dalhancei B (2), along with a known compound epicatechin (3) were isolated from 80% methanol extract of the barks of Dalbergia hancei Benth. The structures of compounds 1–3 were elucidated by comparison with the literature and physical data analysis, including optical rotation, MS, 1D and 2D NMR spectra. Compounds 1 and 2 showed weak inhibitory activity against tyrosinase at 16.22 mmol/L, with inhibition rates of 42.23 ± 0.18% and 45.68 ± 0.17%, respectively; compound 1 exhibited weak inhibitory activity against α-glucosidase with the inhibition rate of 43.72 ± 0.22% at 5.41 mmol/L, compounds 2 and 3 had better α-glucosidase inhibitory activity than compound 1 with IC50 values of 0.90 ± 0.18 and 0.41 ± 0.17 mmol/L, respectively. [ABSTRACT FROM AUTHOR]

Three new compounds (6S,9S)-6′-galloyl-roseoside (1), purpurogallin ethyl carboxylate (2), and tibetana A (3) were isolated from 80% methanol extract of the leaves of Castanopsis tibetana Hance. Their structures were elucidated based on comprehensive spectroscopic methods and chemical data, including optical rotation, UV, MS, 1 D and 2 D NMR spectra. Compounds 1 and 3 were evaluated for their α-glucosidase inhibitory activity, pancreatic lipase inhibitory activity, and tyrosinase inhibitory activity. [ABSTRACT FROM AUTHOR]