Marine natural products are considered to be valuable resources that are furnished with diverse chemical structures and various bioactivities. To date, there are seven compounds derived from marine natural products which have been approved as therapeutic drugs by the U.S. Food and Drug Administration. Numerous bromotyrosine derivatives have been isolated as a type of marine natural products. Among them, psammaplin A, including the oxime groups and carbon–sulfur bonds, was the first identified symmetrical bromotyrosine-derived disulfide dimer. It has been found to have a broad bioactive spectrum, especially in terms of antimicrobial and antiproliferative activities. The highest potential indole-derived psammaplin A derivative, UVI5008, is used as an epigenetic modulator with multiple enzyme inhibitory activities. Inspired by these reasons, psammaplin A has gradually become a research focus for pharmacologists and chemists. To the best of our knowledge, there is no systematic review about the biological activity and structural modification of psammaplin A. In this review, the pharmacological effects, total synthesis, and synthesized derivatives of psammaplin A are summarized.
This paper demonstrates a model kit
comprising a series of silicone
balls with magnets embedded in different predesigned configurations,
which can be used to construct stable models of close-packed crystal structures. Students in the
course of general chemistry lab can use this model kit to construct
the four basic packing structures of identical spheres. In addition,
this paper gives a detailed introduction to how students can better
understand the characteristics of close-packed crystal structures
by learning the unique connection configurations between neighboring
balls in the kit. The instructiveness of using this model kit is also
assessed by summarizing and analyzing the students’ opinions
from the writing assignments and questionnaire survey.
A new ruthenium(II) complex grafted with beta-d-allopyranoside, Ru(bpy)(2)(Happip)(ClO(4))(2) (where bpy = 2,2'-bipyridine; Happip = 2-(4-(beta-d-allopyranoside)phenyl)imidazo[4,5-f][1,10]phenanthroline), has been synthesized and characterized by elemental analysis, (1)H NMR spectroscopy, and mass spectrometry. The acid-base properties of the complex have been studied by UV-visible and luminescence spectrophotometric pH titrations, and ground- and excited-state ionization constants have been derived. The Ru(II) complex functions as a DNA intercalator as revealed by UV-visible and emission titrations, salt effects, steady-state emission quenching by [Fe(CN)(6)](4-), DNA competitive binding with ethidium bromide, DNA melting experiment, and viscosity measurements.
An integrated and inquiry-based experiment on solid state chemistry is applied to an inorganic chemistry lab course to provide insight into the characteristics of the solid phase reaction. In this experiment, students have the opportunity to synthesize long-lasting phosphors with formula xSrO•yAl 2 O 3 :Eu 2+ , Dy 3+ , by means of precipitation and high temperature methods, and to characterize them by powder X-ray diffractometry. The luminescent properties of the phosphors are also suitable for investigation by student research teams with the assistance of solid fluorescence analysis. With a change in the Sr/Al ratio of strontium aluminates, the phosphors show distinct emission bands, and with a change in the content of Dy in a certain range, the different data of luminescence intensity and decay time can be obtained. By analyzing the crystal structures and photoluminescence mechanism of products, students can better understand abstract concepts of luminescent solid materials, including nonstoichiometric compounds, extrinsic point defects, crystalline fields in the solid state, band levels, and hole and electron transfer.
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