查看更多>>摘要：? 2021 Elsevier Ltdortho-Sulfonamide phenols represent a class of attractive structural motifs in medicinal and synthetic chemistry. Herein an efficient metal-free rearrangement reaction has been developed for the construction of ortho-sulfonamide phenols via HFIP-prompted intramolecular sulfonamide group 1,3-migration. This protocol features mild reaction conditions, broad functional group compatibility and good regioselectivity. Combined experimental mechanistic study and detailed DFT calculations clarified the crucial role of HFIP molecules in facilitating this reaction, and the unique hydrogen bond network had been deduced to account for the observed reactivity.
查看更多>>摘要：? 2021 Elsevier LtdAn unexpected Brosnted acid-catalyzed cascade reaction of 1,3-dimethyl-6-aminouracil with 2-hydroxychalcone has been developed to afford pyrido[2,3–d]pyrimidine-2,4-diones derivatives and 2,8-dioxabicyclo[3.3.1]nonane derivatives in moderate to good yields. This method not only establishes a new transformation of 1,3-dimethyl-6-amino-uracil and 2-hydroxychalcone but also provides an efficient method for the synthesis of pyrido[2,3–d]pyrimidine-2,4-diones and 2,8-dioxabicyclo[3.3.1]nonane derivatives.
查看更多>>摘要：? 2021 Elsevier LtdHerein we present the plain manufacture of sterically hindered tertiary alkyl thioethers via the Cu-catalyzed coupling of unactivated tertiary alkyl alcohols with thio-alcohols/phenols. The present strategy with easy-to-operate reaction conditions represents one of the most effective unactivated tertiary C(sp3)–S bond-forming methods via readily accessible Lewis acid catalysis. Moreover, this protocol has high functional group compatibility and wide substrate adaptability.
查看更多>>摘要：? 2021 Elsevier LtdDetection of pyrophosphate (PPi) can be used to monitor gene replication, transcription, and other forms of enzymatic DNA/RNA synthesis, but it can be difficult to perform in real samples because of the presence of many other biomolecules and buffer components. In this study we prepared a colorimetric probe that could detect PPi specifically and selectively in the presence of cysteine, dithiothreitol (DTT), nucleoside triphosphates, and human serum (containing several biomolecules and amino acids). Among four candidate rhodamine derivatives, we found that the copper complex 1 could detect PPi uniquely, even in the presence of several competing biomolecules. The copper complex 1 also exhibited its highly selective PPi sensing capability when applied to rolling circle amplification and in vitro transcription in samples containing high concentrations of DTT, making it a promising candidate for colorimetric detection of RNA/DNA when using amplification techniques.
查看更多>>摘要：? 2021 Elsevier LtdThree unprecedented tetracyclic and pentacyclic isomalabaricanes, named rhabdaglostelones A-C (1–3), were isolated from the marine sponge Rhabdastrella globostellata. Their chemical structures were determined by extensive analyses of HR-ESI-MS, 1D- and 2D-NMR spectra. Absolute configurations of them were identified by experimental and TD-DFT theoretical calculated ECD spectra. The tetracyclic and pentacyclic backbone are predicted biological generation from isomalabaricane triterpenoid, a unique compound class in the Rhabdastrella species. Compounds 1 and 2 exhibited cytotoxic activities toward LU1, HepG2, MCF7, and SKMel2 cell lines with their IC50 values ranging from 15.91 ± 1.21 to 23.21 ± 1.89 μM, while compound 3 was inactivity on these cancerous cell lines.
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