Solvent-free enantioselective conjugate addition and bioactivities of nitromethane to Chalcone containing pyridine
作者:Guoping Zhang、Chun Zhu、Dengyue Liu、Jianke Pan、Jian Zhang、Deyu Hu、Baoan Song
DOI:10.1016/j.tet.2016.11.063
日期:2017.1
catalysts in the enantioselective Michael additions of nitromethane to α,β-unsaturated ketones containing pyridine. The best results were obtained with the bifunctional catalyst prepared from 3,5-di(trifluoromethyl)-aniline under solvent-free conditions. This thiourea promoted the reaction with high enantioselectivities and chemical yields for aryl ketones. The origins of enantioselectivity were further
Physical Organic Study of StructureâActivityâEnantioselectivity Relationships in Asymmetric Bifunctional Thiourea Catalysis: Hints for the Design of New Organocatalysts
Correlations of pKa with catalytic activity and stereoselectivity were determined and linear free energy relationships (LFERs) were observed for both pKa−log (k) and pKa−log (R/S) correlations in meta‐ and/or para‐substituted aromatic thioureas (see figure). These results provided a basis for new catalyst development and several improved catalysts were identified in our initial attempts.
酸度效应:确定了p K a与催化活性和立体选择性之间的相关性,并在meta ‐中的p K a -log(k)和p K a -log(R / S)相关性中观察到线性自由能关系(LFER)。和/或对位取代的芳族硫脲(见图)。这些结果为新催化剂的开发提供了基础,并且在我们最初的尝试中发现了几种改进的催化剂。
Thiourea-Catalyzed Enantioselective Fluorination of β-Keto Esters
Bifunctional chiral thioureas have been successfully used as organocatalysts in enantioselectivefluorinations of β-ketoesters. The corresponding products could be obtained with good to excellent enantioselectivity in high yields by using N-fluorobisbenzenesulphonimide (NFSI) as fluorination reagent.
Synthesis, antibacterial and anti-MRSA activity, in vivo toxicity and a structure–activity relationship study of a quinoline thiourea
作者:Niamh Dolan、Declan P. Gavin、Ahmed Eshwika、Kevin Kavanagh、John McGinley、John C. Stephens
DOI:10.1016/j.bmcl.2015.11.058
日期:2016.1
We report the synthesis, antibacterial evaluation of a series of thiourea-containing compounds. 1-(3,5-Bis (trifluoromethyl) phenyl)-3-((S)-(6-methoxyquinolin-4-yl)-((1S, 2S, 4S, 5R)-5-vinylquinuclidin-2-yl) methyl) thiourea 5, was the most active against a range of Gram-positive and Gram-negative bacteria, and exhibited bacteriostatic activity against methicillin resistant Staphylococcus aureus (MRSA) comparable to that of the well-known antibacterial agent vancomycin. Quinoline thiourea 5 was subjected to a detailed structure-activity relationship study, with 5 and its derivatives evaluated for their bacteriostatic activity against both Gram-negative and Gram-positive bacteria. A number of structural features important for the overall activity of quinoline thiourea 5 have been identified. A selection of compounds, including 5, was also evaluated for their in vivo toxicity using the larvae of the Greater wax moth, Galleria mellonella. Compound 5, and a number of derivatives, were found to be non-toxic to the larvae of Galleria mellonella. A new class of antibiotic can result from the further development of this family of compounds. (C) 2015 Elsevier Ltd. All rights reserved.