Search

Molecules with diterpene skeletons often possess valuable medicinal properties. Two new diterpenes 1α,6α,7β-triacetoxy-5α-hydroxy-14β-ethyl-O-vouacapane (1) and 2α-acetoxy-14,15-cyclopimara-7β,16-diol (2) were isolated from the seeds of Caesalpinia minax Hance. Their structures were established on the basis of extensive spectroscopic analyses, including HR-ESI-MS, UV, IR, 1D, and 2D NMR (HSQC, HMBC, NOESY) methods. The stereochemical structure of 1 was confirmed via the circular dichroism spectrum and calculated ECD experiment. The inhibitory activity of nitric oxide production of RAW264.7 macrophages stimulated by lipopolysaccharide of compounds 1 and 2 was evaluated, and compound 1 was found to show significant inhibitory effect. [ABSTRACT FROM AUTHOR]

Four compounds were isolated from Daphne giraldii callus cells, and their structures were characterized as daphnenone (1), daphnolon (2), R-(−)-1-(4′-hydroxyphenyl)-3-hydroxy-5-phenyl-1,5-pentandione (3), and S-(+)-daphneolone-4′-O-β-d-glucoside (4) on the basis of MS, NMR spectrographic analysis, and chemical methods. All of the four compounds possessed C6-C5-C6 carbon skeleton, and among them, 3 and 4 were two new compounds. In activity screening test, compounds 1, 2, 3, and 4 showed different degrees of cytotoxic activity against the tumor cells of human melanoma A375-S2 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium hydrobromide method, with IC50 values of 29.8, 51.0, 41.0, and 150.0 μM, respectively. Furthermore, we found the important target which could explain the cytotoxic mechanism of the four compounds by using autodock 4.0, a structure-guided discovery approach, and the important residues CYS532, GLY534, and SER535 of B-Raf kinase have been discovered. [ABSTRACT FROM AUTHOR]

Three new cassane-diterpene-lactones, methyl 1α,7β-diacetoxy-5α,12α-dihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (1), methyl 7β-acetoxy-1α,5α,12α-trihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (2), and 12α-ethoxyl-1α,6α,7β-triacetoxy-5α,14β-dihydroxy-cass-13(15)-en-16,12-olide (3), were isolated from the seeds of Caesalpinia minax Hance. Their structures were established on the basis of HR-ESI-MS, 1D and 2D NMR spectral analysis. [ABSTRACT FROM AUTHOR]

The chemical constituent research on the ethyl acetate extracts of fermentation liquid of the marine fungus Trichoderma atroviride G20-12 led to the isolation of two new compounds, 2-hydroxybutan-3-yl 5'-(2''-hydroxy-N-(2'''-oxobutan-3'''-yl)propanamido)butanoate (1) and 3-hydroxy-5-(4-hydroxybenzyl)dihydrofuran-2(3H)-one (2). The structures of the new compounds were determined by spectroscopic and chemical analysis. [ABSTRACT FROM AUTHOR]

From the dried aerial part of Acanthopanax senticosus, a new coumarin glycoside, eleutheroside B2 (1), and a new sesquiterpenoid, oplopanone B (2), were isolated. Their structures were elucidated on the basis of chemical and spectroscopic methods. [ABSTRACT FROM AUTHOR]

To cultivate students' comprehensive experimental quality, this paper analyzes present situation of SMT experiment teaching in Guilin University of Electronic Technology. Many shortcomings and the insufficiency of SMT experiment are reported, and experimental teaching mode and reform measures are explored, such as dynamic integration of the experimental auxiliary teaching software and the network experimental teaching plattorm. We also pay attention to cultivate students'comprehensive qualit and innovation a hill , and make the students from passive learning to active learning. Those make up for the inadequacy of traditional experimental teaching methods effectively. To make full use of lahoratory equipment resources, the SMT virtual experiment aided teaching software is developed and the network experimental teaching plattorm is estahlished. Those aU improve the students'interess in experiments, expand the SMT experimental teaching method and ohtain good experiment teaching results. [ABSTRACT FROM AUTHOR]

• C(sp2)–H bond activation reactions of N -(hetero)aryl-7-azaindoles. • Cross-coupling with α-carbonyl sulfoxonium ylides. • High regioselectivity. • Excellent chemical yields and good functional group tolerance. We described a protocol for rhodium-catalyzed C(sp2)–H bond activation reactions of N- (hetero)aryl-7-azaindoles and cross-coupling with α-carbonyl sulfoxonium ylides. In the C–H activation reaction, the 7-azaindole moiety acts as a directing group, which results in high regioselectivity. The protocol features excellent chemical yields and good functional group tolerance. [ABSTRACT FROM AUTHOR]