Search results for "Acrolein"
showing 5 items of 45 documents
Polymere acroleine, 2. Mitt. Reaktionen und konstitution des disacryls
1956
Disacryl ist ein Polymerisationsprodukt des Acroleins, dessen Struktur bisher nicht geklart war. Obwohl es vollstandig unloslich ist, konnte es mit einer Reihe typischer Aldehydreagentien umgesetzt werden. Die Umsetzungsprodukte sinde in verschiedenen Losungsmitteln loslich; sie sind makromolekular. Es wird eine Strukturformel fur Disacryl vorgeschlagen. Disacryl is a polymerization product of acrolein and until now of unknown structure. In spite of its complete insolubility one can react it with typical aldehyd reagents. The reaction products are soluble in common solvents and are recognised as macromoleculare substances. A formula of disacryl is proposed.
Über die anionische polymerisation von acrolein. Polymere acroleine. 34. Mitt.1
1967
Acrolein wurde mit Lithium-, Natrium- oder Kaliumcyanid in Tetrahydrofuran bzw.in Toluol polymerisiert. Die Abhangigkeit der Polymerisationsgeschwindigkeit und der Struktur der Polymeren von Reaktionsmedium, Temperatur und Gegenion wurde untersucht. Unterhalb -10°C polymerisiert Acrolein mit Natriumcyanid nur uber die CO. Doppelbindung. Es entstehen hochmolekulare, losliche Poly-3,4-acroleine. Oberhalb -10°C wird dagegen auch Polymerisation uber die Vinylgruppe beobachtet. Die Kurve fur die Abhangigkeit der Polymerisationsgeschwindigkeit von der Reaktionstemperatur durchlauft Extremwerte. Es wird ein Mechanismus aufgestellt, der die jeweilige Struktur des Polymeren als Ergebnis von Gleichge…
A DFT study of the Diels–Alder reaction between methyl acrolein derivatives and cyclopentadiene. Understanding the effects of Lewis acids catalysts b…
2006
Abstract The effects of Lewis acid catalysts based on sulfur containing boron heterocycles on the Diels–Alder reactions of two methyl acroleins with cyclopentadiene have been studied using DFT methods. These reactions take place along highly asynchronous concerted processes. While the reaction with crotonaldehyde leads to the expected endo adduct, the reaction with methacrolein leads to exo one in agreement with the experiments. The catalytic effect can be explained through the analysis of the electrophilicity index (ω) of the reagents, and the molecular structure of the corresponding transition structures.
Cinnamaldehyde Induces Expression of Efflux Pumps and Multidrug Resistance in Pseudomonas aeruginosa
2019
Essential oils or their components are increasingly used to fight bacterial infections. Cinnamaldehyde (CNA), the main constituent of cinnamon bark oil, has demonstrated interesting properties in vitro against various pathogens, including Pseudomonas aeruginosa. In the present study, we investigated the mechanisms and possible therapeutic consequences of P. aeruginosa adaptation to CNA. Exposure of P. aeruginosa PA14 to subinhibitory concentrations of CNA caused a strong albeit transient increase in the expression of operons that encode the efflux systems MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY/OprM. This multipump activation enhanced from 2- to 8-fold the resistance (MIC) of PA14 to …
Organocatalytic Oxa-Michael/Michael/Michael/Aldol Condensation Quadruple Domino Sequence : Asymmetric Synthesis of Tricyclic Chromanes
2018
An efficient and highly stereoselective one-pot, four-component synthesis of functionalized tricyclic chromanes has been achieved through an organocatalyzed quadruple domino reaction. The reaction sequence involves an oxa-Michael/Michael/Michael/aldol condensation between alcohols, 2 equiv of acrolein, and nitrochromenes to generate the pharmaceutically important tricyclic chromanes bearing three contiguous stereogenic centers including a chiral tetrasubstituted carbon center in good domino yields (30–70%) and excellent diastereo- and enantioselectivities (>20:1 dr and >99% ee). peerReviewed