Search results for "rafts"

Enantioselective Friedel-Crafts Alkylation of Indoles with (E)-1-Aryl-4-benzyloxybut-2-en-1-ones Catalyzed by an (R)-3,3′-Br2BINOLate-Hafnium(IV) Com…

2013

A highly enantioselective Friedel–Crafts reaction of unprotected indoles with (E)-1-aryl-4-benzyloxybut-2-en-1-ones catalyzed by a new chiral [Hf{(R)-3,3′-Br2-BINOL}(OtBu)2]2 complex has been developed to functionalize the C-3 position of the indole nucleus with a side chain bearing a 1,4-difunctionalized moiety and a benzylic stereogenic center. The reaction proceeds in good to excellent yields and excellent enantioselectivities (up to 97 % ee). The usefulness of this approach was illustrated with the synthesis of a tryptophol derivative.

Catalytic Asymmetric Friedel–Crafts Alkylations in Total Synthesis

2009

Synthesis of Functionalized Indoles with a Trifluoromethy-Substituted Stereogenic Tertiary Carbon Atom Through an Enantioselective Friedel-Crafts Alk…

2010

[EN] Chiral complexes of BINOL-based ligands with zirconium tert-butoxide catalyze the Friedel-Crafts alkylation reaction of indoles with beta-trifluoromethyl-alpha,beta-unsaturated ketones to give functionalized indoles with an asymmetric tertiary carbon center attached to a trifluoromethyl group. The reaction can be applied to a large number of substituted alpha-trifluoromethyl enones and substituted indoles. The expected products were obtained with good yields and ees of up to 99%.

Organocatalytic Enantioselective Friedel–Crafts Aminoalkylation of Indoles in the Carbocyclic Ring

2016

The first general catalytic method for the, so far elusive, enantioselective Friedel−Crafts functionalization of indoles in the carbocyclic ring is presented. This transformation contrasts with the usual tendency of these heterocycles to react at the azole ring. For this purpose, the four regioisomeric hydroxy carbocyclic-substituted indoles were reacted with several isatinderived ketimines, using a Cinchona alkaloid-based squaramide, in a low 0.5−5 mol % catalyst loading, as a bifunctional catalyst. This methodology allows the functionalization of indoles in every position of the carbocyclic ring in a regio- and enantioselective fashion, by switching only the position of the hydroxy group …

Cholesterol Dependence of Collagen and Echovirus 1 Trafficking along the Novel α2β1 Integrin Internalization Pathway

2013

We have previously shown that soluble collagen and a human pathogen, echovirus 1 (EV1) cluster α2β1 integrin on the plasma membrane and cause their internalization into cytoplasmic endosomes. Here we show that cholesterol plays a major role not only in the uptake of α2β1 integrin and its ligands but also in the formation of α2 integrin-specific multivesicular bodies (α2-MVBs) and virus infection. EV1 infection and α2β1 integrin internalization were totally halted by low amounts of the cholesterol-aggregating drugs filipin or nystatin. Inhibition of cholesterol synthesis and accumulation of lanosterol after ketoconazole treatment inhibited uptake of collagen, virus and clustered integrin, an…

Organocatalytic Enantioselective Synthesis of α-Hydroxyketones through a Friedel−Crafts Reaction of Naphthols and Activated Phenols with Aryl- and Al…

2016

[EN] An efficient organocatalytic asymmetric synthesis of alpha-hydroxyketones has been developed. Quinine-derived thiourea catalyzed the enantioselective Friedel Crafts alkylation of naphthols and activated phenols with aryl- and alkylglyoxal hydrates, providing the corresponding chiral alpha-hydroxyketones with high yields (up to 97%) and excellent enantioselectivities (up to 99% ee).

Former for lek En empirisk analyse av møtet mellom barn og åpen form.

2015

Masteroppgave kunstfag- Universitetet i Agder, 2015 Denne oppgaven kan leses som et møte mellom barn og åpen form. Empirien utgjør materialet fra en observasjon der barn i en barnehage får nye formelementer som er laget spesielt for denne oppgaven. Problemstillingen i oppgaven er Hvordan kan åpne former skape fantasi i barns lek? Utgangspunktet er at barn kan leke med apparater og leketøy som enten har en bestemt funksjon, eller en mer åpen utforming, der gjenstanden ikke nødvendigvis viser at er noe, nærmere bestemt har en åpen form. I pedagogikken til Friedrich Frøbel fremholdes de åpne formene som fordelaktige, da de skaper fantasi og læring. Oppgaven viser også til kunstneren Gjedrem, s…

Vibrasjonsanalyse : Feildeteksjon i Kulelager: Prosessering av Vibrasjonssignaler, Algoritmer, og Envelope Spektrum

2017

Masteroppgave fornybar energi ENE500 - Universitetet i Agder 2017 The report deals with fault detection and diagnosis of roller element bearings. Vibration and shaft position sensor data combined with three algorithms are tested to determine which combination may detect bearing faults early and reliably. Experimental data from an accelerated life-time test is used to verify the performance. Results show that the vibration signal combined with a fast spectral correlation algorithm yields the most reliable diagnosis.

Catalytic activity of rare-earth-supported catalysts in Friedel–Crafts acylations

1999

Abstract Friedel–Crafts acylations are catalysed by rare-earth-supported catalysts. The preparation, characterization and performance of these solid catalysts in a test acylation reaction and in a variety of syntheses of aromatic ketones are reported. In contrast to the reactions using AlCl3, the experimental conditions are non-polluting and the final work-up does not require any aqueous treatment.

Lanthanide bis(trifluoromethylsulfonyl)amides vs. trifluoromethylsulfonates as catalysts for Friedel–Crafts acylations

2002

Abstract The use of catalytic amounts: 1 mol% or less of perfluoroalkyl lanthanide salts as homogeneous catalysts for Friedel–Crafts acylations in non-hazardous solvents is thereafter investigated. Lanthanide bis(trifluoromethylsulfonyl)amides are better catalysts than the triflate analogues towards the acetylation of activated aromatic rings.