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61.
The Hydrazine–O2 Redox Couple as a Platform for Organocatalytic Oxidation: Benzo[c]cinnoline‐Catalyzed Oxidation of Alkyl Halides to Aldehydes
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Ilana B. Stone Dr. Janis Jermaks Dr. Samantha N. MacMillan Prof. Tristan H. Lambert 《Angewandte Chemie (International ed. in English)》2018,57(38):12494-12498
An organocatalytic oxidation platform that capitalizes on the capacity of hydrazines to undergo rapid autoxidation to diazenes is described. Commercially available benzo[c]cinnoline is shown to catalyze the oxidation of alkyl halides to aldehydes in a novel mechanistic paradigm involving nucleophilic attack, prototropic shift, and hydrolysis. The hydrolysis and reoxidation events occur readily with only adventitious oxygen and water. A survey of the scope of viable substrates is shown along with mechanistic and computational studies that give insight into this mode of catalysis. 相似文献
62.
Dimitrios A. Lamprou James R. Smith Thomas G. Nevell Eugen Barbu Corinne Stone Colin R. Willis Richard J. Ewen John Tsibouklis 《Surface science》2010,604(5-6):541-547
Self-assembled structures of alkanethiols that have been deposited on gold from ethanolic solutions are susceptible to both chemical and physical changes: ethanol provides a medium for the formation of S-alkyl hydrogen thiocarbonates and related compounds via reaction with dissolved, atmospheric, CO2. Deposition from ethanolic solutions results in multilayered structures incorporating these compounds, which at room temperature are susceptible to time-dependent structural rearrangement and molecular migration. 相似文献
63.
Muramatsu H Richichi SJ Severini H Skubic P Dytman SA Mueller JA Nam S Savinov V Chen S Hinson JW Lee J Miller DH Pavlunin V Shibata EI Shipsey IP Cronin-Hennessy D Lyon AL Park CS Park W Thorndike EH Coan TE Gao YS Liu F Maravin Y Narsky I Stroynowski R Artuso M Boulahouache C Bukin K Dambasuren E Khroustalev K Mountain R Nandakumar R Skwarnicki T Stone S Wang JC Mahmood AH Csorna SE Danko I Bonvicini G Cinabro D Dubrovin M McGee S Bornheim A Lipeles E Pappas SP Shapiro A Sun WM Weinstein AJ 《Physical review letters》2002,89(25):251802
In e(+)e(-) collisions using the CLEO detector, we have studied the decay of the D0 to the final state K(0)(S)pi(+)pi(-) with the initial flavor of the D0 tagged by the decay D(*+)-->D0pi(+). We use the Dalitz technique to measure the resonant substructure in this final state and clearly observe ten different contributions by fitting for their amplitudes and relative phases. We observe a K(*)(892)(+)pi(-) component which arises from doubly Cabibbo suppressed decays or D0-D0; mixing. 相似文献
64.
Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Thayer JB Von Toerne E Wilksen T Zoeller MM Muramatsu H Richichi SJ Severini H Skubic P Dytman SA Mueller JA Nam S Savinov V Chen S Hinson JW Lee J Miller DH Pavlunin V Shibata EI Shipsey IP Cronin-Hennessy D Lyon AL Park CS Park W Thorndike EH Coan TE Gao YS Liu F Maravin Y Stroynowski R Artuso M Boulahouache C Bukin K Dambasuren E Khroustalev K Mountain R Nandakumar R Skwarnicki T Stone S Wang JC Mahmood AH 《Physical review letters》2002,89(25):251801
We report on a search for charmless hadronic B decays to the three-body final states K(0)(S)h(+)pi(-), K(+)h(-)pi(0), K(0)(S)h(+)pi(0) (h(+/-) denotes a charged pion or kaon), and their charge conjugates, using 13.5 fb(-1) of integrated luminosity produced near sqrt[s]=10.6 GeV, and collected with the CLEO detector. We observe the decay B-->K0pi(+)pi(-) with a branching fraction (50(+10)(-9)(stat.)+/-7(syst.))x10(-6) and the decay B-->K(*+)(892)pi(-) with a branching fraction (16(+6)(-5)(stat.)+/-2(syst.))x10(-6). 相似文献
65.
Nontrivial steady flows have recently been found that capture the main structures of the turbulent buffer layer. We study the effects of polymer addition on these "exact coherent states" (ECS) in plane Couette flow. Despite the simplicity of the ECS flows, these effects closely mirror those observed experimentally: Structures shift to larger length scales, wall-normal fluctuations are suppressed while streamwise ones are enhanced, and drag is reduced. The mechanism underlying these effects is elucidated. These results suggest that the ECS are closely related to buffer layer turbulence. 相似文献
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69.
Bengt Aspvall Richard E Stone 《Journal of Algorithms in Cognition, Informatics and Logic》1980,1(1):1-13
L. G. Khachiyan's polynomial time algorithm for determining whether a system of linear inequalities is satisfiable is presented together with a proof of its validity. The algorithm can be used to solve linear programs in polynomial time. 相似文献
70.
R. Daniel Little George W. Muller Manuel G. Venegas Gary L. Carroll Ahmed Bukhari Larry Patton Keith Stone 《Tetrahedron》1981,37(25):4371-4383
A comparison of the inter- and intramolecular diyl trapping routes to linearly fused tricyclopentanoids is presented. In addition, several of the factors which are responsible for the stereoselectivity which is associated with the intramolecular process are examined and it is concluded that conformational rather than electronic (secondary orbital) factors play the dominant role. It is shown that gem methyl groups located on the acyclic chain which joins the diyl and diylophile (in reference to 32 and 35, but not to 47) have no practical effect upon the outcome of the trapping reaction. The intramolecular process is stereospecific with respect to diylophile geometry, and highly stereoselective with respect to the ring junction stereochemistry. Finally, an abortive attempt to synthesize the marine natural product Δ9(12)-capnellene (19) as well as a successful synthesis of the mold metabolite d,l- hirsutene (18) is presented. 相似文献