109899-90-3Relevant academic research and scientific papers
Novel Bifunctionalization of Activated Methylene: Base-Promoted Trifluoromethylthiolation of β-Diketones with Trifluoromethanesulfinyl Chloride
Sun, Dong-Wei,Jiang, Min,Liu, Jin-Tao
, p. 10797 - 10802 (2019)
A novel bifunctionalization of activated methylene was achieved successfully through the base-promoted trifluoromethylthiolation of β-diketones or β-ketoesters with trifluoromethanesulfinyl chloride. A series of α-trifluoromethylthiolated α-chloro-β-diketones and α-chloro-β-ketoesters were obtained in moderate to good yields under mild conditions. When β-diketones containing a phenyl group with a hydroxyl or amino substituent at the ortho position were used as substrates, intramolecular trifluoromethylthiolation/cyclization reaction took place to give the corresponding cyclic products. Furthermore, the protocol could be extended to perfluoroalkylthiolation with the sodium perfluoroalkanesulfinate/POCl3 system. On the basis of experimental results, plausible mechanisms are proposed.
Cu(II)-catalyzed oxidative esterification of 2-carbonyl substituted phenols from the alcohol oxidation level
Sharma, Satyasheel,Park, Jihye,Kim, Mirim,Kwak, Jong Hwan,Jung, Young Hoon,Kim, In Su
, p. 9391 - 9397 (2013/10/08)
A copper-catalyzed oxidative esterification of 2-carbonyl substituted phenols from the alcohol oxidation level is described. This protocol represents direct access to a range of 2-carbonylated aryl benzoate derivatives, which are important building blocks in the synthesis of natural and pharmacological compounds.
Antimicrobial effects of novel siderophores linked to β-lactam antibiotics
Kline,Fromhold,McKennon,Cai,Treiberg,Ihle,Sherman,Schwan,Hickey,Warrener,Witte,Brody,Goltry,Barker,Anderson,Tanaka,Shawar,Nguyen,Langhorne,Bigelow,Embuscado,Naeemi
, p. 73 - 93 (2007/10/03)
As a strategy to increase the penetration of antibiotic drugs through the outer membrane of Gram-negative pathogens, facilitated transport through siderophore receptors has been frequently exploited. Hydroxamic acids, catechols, or very close isosteres of catechols, which are mimics of naturally occurring siderophores, have been used successfully as covalently linked escorting moieties, but a much wider diversity of iron binding motifs exists. This observation, coupled to the relative lack of specificity of siderophore receptors, prompted us to initiate a program to identify novel, noncatechol siderophoric structures. We screened over 300 compounds for their ability to (1) support growth in low iron medium of a Pseudomonas aeruginosa siderophore biosynthesis deletion mutant, or (2) compete with a bactericidal siderophore-antibiotic conjugate for siderophore receptor access. From these assays we identified a set of small molecules that fulfilled one or both of these criteria. We then synthesized these compounds with functional groups suitable for attachment to both monobactam and cephalosporin core structures. Siderophore-β-lactam conjugates then were tested against a panel of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus strains. Although several of the resultant chimeric compounds had antimicrobial activity approaching that of ceftazidime, and most compounds demonstrated very potent activity against their cellular targets, only a single compound was obtained that had enhanced, siderophore-mediated antibacterial activity. Results with tonB mutants frequently showed increased rather than decreased susceptibilities, suggesting that multiple factors influenced the intracellular concentration of the drugs. (C) 2000 Elsevier Science Ltd.
Reactions of Carbonyl Compounds in Basic Solutions. Part 11. The Baker-Venkataraman Rearrangement
Bowden, Keith,Chehel-Amiran, Mohsen
, p. 2039 - 2044 (2007/10/02)
The detailed mechanism of the Baker-Venkataraman rearrangement has been studied.The kinetics of the rearrangement of a series of 2-acetylphenyl 3- or 4-substituted benzoates and acetylnaphthyl benzoates catalysed by a basic 'non-nucleophilic' buffer in dimethyl sulphoxide have been measured.Studies of substituent effects, kinetic isotope effects, and acidity function correlations indicate a pathway involving pre-equilibrium formation of the carbanion, followed by rate-determining intramolecular nucleophilic attack.The methanolysis of the 2-acetylphenyl benzoates catalysed by methoxide in methanolic dimethyl sulphoxide has been similary investigated.In this case the pathway appears to involve neighbouring group participation by the ketonic carbonyl group.
