查看更多>>摘要：A novel method was developed for the synthesis of carbamoyl azides from hydroxamic acids via the Lossen rearrangement using diphenyl phosphorazidate, which acts as both the activator and azide source to produce the azides via an isocyanate intermediate. Using this method, various hydroxamic acids were converted into the corresponding carbamoyl azides, enabling their preparation without the use of highly explosive reagents.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Two new compounds, namely an uncommon eunicellin-based diterpenoid (clakrefielin A, 2) and a 9, 11secosteroid (cladiellasterol A, 4), along with a known carotenoid (all-trans-peridinin, 7), were isolated from the Ximao Island, Sanya Bay soft coral Cladiella krempfi. The structures of these compounds were established on the basis of extensive spectroscopic analysis, X-ray diffraction analysis, chemical transformations, as well as the comparison with the reported data in the literature. The biological activities of these compounds were investigated, and compound 7 was found to be a new protein tyrosine phosphatase 1B (PTP1B) inhibitor (IC50 = 7.2 lM). (C)& nbsp;2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A novel pterocarpan, named phaseollin A (1) was isolated from Lima bean (the seeds of Phaseolus lunatus L.). The structure of 1 was elucidated by the extensive spectroscopic analysis (1D and 2D NMR, HR-ESIMS) as well as the experimental and calculated ECD data analysis. Compound 1 showed moderate activity of inhibiting NO production on lipopolysaccharide (LPS)-induced RAW264.7 cells with IC50 value of 37.13 & nbsp;+/- 2.58 lM.(C 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A convenient and novel route for the stereoselective synthesis of 3,5-Di-O-benzoyl-2-deoxy-2-chloro-2-C-methyl-D-ribono-c-lactone 5a and its analogues is developed by an Evans-Aldol reaction in the presence of TiCl4. Starting from 2-chloropropionyl chloride, 5a is efficiently and regioselectively produced on a kilogram scale in an overall yield of 32% with an HPLC purity of 98% by area. In addition, this approach allowed an efficient synthesis of 3,5-Di-O-benzoyl-2-deoxy-2-fluoro-2-C-methyl-D-ribono-c- lactone 5b in a total 20% yield. (C)& nbsp;2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：We report a cesium bicarbonate-mediated alkylation of 2,4-dihydroxybenzyaldehyde and 2,4-dihydroxyacetophenone to generate 4-alkylated products in acetonitrile at 80 degrees C with excellent regioselectivity, up to 95% isolated yields, and broad substrate scope.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Herein, the synthesis of 6,7-benzene-fused tropane derivatives from isoindoline-aminal hybrid compound has been reported. In the present synthetic study, ring-closing metathesis (RCM) was employed to construct the 6,7-benzene-fused tropene skeleton. To obtain the desired cis-1-allyl-3-stylylisoindoline precursor for the RCM reaction, the diastereoselective aza-Hosomi-Sakurai allylation and functional group transformations of isoindoline-aminal hybrid compound were performed. Using the synthesized 6,7-benzene-fused tropene derivative as a versatile precursor, synthesis of several 6,7-benzene-fused tropane derivatives was demonstrated by the transformations of the internal alkene moiety.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A squaramide organocatalyst efficiently promoted the asymmetric Friedel-Crafts alkylation of oc,6-unsat-urated trifluoromethyl ketones with aromatic alcohols in a one-pot procedure, affording corresponding 6trifluoromethyl-substituted 7,8-dihydrochromen-6-ol derivatives (up to 94% yield, 74% ee). (C)& nbsp;& nbsp;2022 Elsevier Ltd. All rights reserved.
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