Search results for "Cyclopropane"
showing 10 items of 104 documents
Roflumilast N-oxide inhibits bronchial epithelial to mesenchymal transition induced by cigarette smoke in smokers with COPD.
2014
Abstract Background Epithelial to mesenchymal transition (EMT) is under discussion as a potential mechanism of small airway remodelling in COPD. In bronchial epithelium of COPD and smokers markers of EMT were described. In vitro, EMT may be reproduced by exposing well-differentiated human bronchial epithelial cells (WD-HBEC) to cigarette smoke extract (CSE). EMT may be mitigated by an increase in cellular cAMP. Objective This study explored the effects of roflumilast N-oxide, a PDE4 inhibitor on CSE-induced EMT in WD-HBEC and in primary bronchial epithelial cells from smokers and COPD in vitro. Methods WD-HBEC from normal donors were stimulated with CSE (2.5%) for 72 h in presence of roflum…
Simvastatin Increases the Ability of Roflumilast N-oxide to Inhibit Cigarette Smoke-Induced Epithelial to Mesenchymal Transition in Well-differentiat…
2014
Cigarette smoking contributes to epithelial-mesenchymal transition (EMT) in COPD small bronchi as part of the lung remodeling process. We recently observed that roflumilast N-oxide (RNO), the active metabolite of the PDE4 inhibitor roflumilast, prevents cigarette smoke-induced EMT in differentiated human bronchial epithelial cells. Further, statins were shown to protect renal and alveolar epithelial cells from EMT. To analyze how RNO and simvastatin (SIM) interact on CSE-induced EMT in well-differentiated human bronchial epithelial cells (WD-HBEC) from small bronchi in vitro. Methods: WD-HBEC were stimulated with CSE (2.5%). The mesenchymal markers vimentin, collagen type I and α-SMA, the e…
ChemInform Abstract: Palladium-Catalyzed Skeletal Rearrangement of Spirotricyclic Olefins: A Facile One-Pot Strategy for the Synthesis of a Novel Mot…
2013
The first utilization of acyclic cyclopropane bearing spirocyclic olefines for the generation of stereospecific complex fused ring systems with an achiral catalyst is reported.
The re Structure of Cyclopropane
2000
A long-standing controversy regarding the re structure of cyclopropane is resolved by performing high-level quantum chemical calculations and analyzing the experimental rotational constants for C3H6 and C3H4D2 augmented by calculated vibrational corrections. For the latter, a least-squares fit yields the following set of parameters: re (CC) = 1.5030(10) A, re(CH) = 1.0786(10) A, and αe(HCH) = 114.97(10)°, which compare favorably with both the pure computational result obtained at the CCSD(T)/cc-pVQZ level as well as an earlier estimate of the re structure of cyclopropane based on analysis of gas-phase electron diffraction data. Our results are in rather poor agreement with a structure base…
Theoretical study of the mechanism of branching rearrangement of carbenium ions
1996
Abstract Owing to the practical interest of the acid catalyzed isomerization reactions of hydrocarbons, the mechanism of the branching rearrangements of C 4 H 9 + and C 5 H 11 + carbenium ions has been studied theoretically using ab initio methods which include electron correlation and extended basis sets. It has been found that the protonated cyclopropane-type species does not appear as a common intermediate for these reactions, since it is a transition state and not a minimum on the potential energy surfaces studied. In the case of C 4 H 9 + cation, the protonated methyl-cyclopropane ring is the transition state for the carbon scrambling reaction in the secondary n-butyl cation, while the…
ChemInform Abstract: Chemical and Spectroscopical Properties of Medium Sized trans- and cis- Bicyclo(n.1.0)alk-2-ynes.
2010
Chemical and spectroscopical properties of cis- and trans-cyclopropano-anellated cycloalkynes of medium ring size are investigated and compared with results from force field calculations. IR and 13C-NMR data of the alkynes reflect the deformation of the triple bond due to ring strain. Parallel to bending the reactivity increases with decreasing ring size, the trans fused alkynes prove to be nearly as reactive as the cis fused with a two carbon smaller ring size. The bicycloalkynes are complexed with silver triflate. 13C NMR reveals that the triple bond as well as the cyclopropane serve as ligands.
CCDC 245912: Experimental Crystal Structure Determination
2006
Related Article: R.Frohlich, T.C.Rosen, O.G.J.Meyer, K.Rissanen, G.Haufe|2006|J.Mol.Struct.|787|50|doi:10.1016/j.molstruc.2005.10.033
CCDC 245917: Experimental Crystal Structure Determination
2006
Related Article: R.Frohlich, T.C.Rosen, O.G.J.Meyer, K.Rissanen, G.Haufe|2006|J.Mol.Struct.|787|50|doi:10.1016/j.molstruc.2005.10.033
CCDC 280354: Experimental Crystal Structure Determination
2006
Related Article: R.Frohlich, T.C.Rosen, O.G.J.Meyer, K.Rissanen, G.Haufe|2006|J.Mol.Struct.|787|50|doi:10.1016/j.molstruc.2005.10.033
CCDC 245908: Experimental Crystal Structure Determination
2006
Related Article: R.Frohlich, T.C.Rosen, O.G.J.Meyer, K.Rissanen, G.Haufe|2006|J.Mol.Struct.|787|50|doi:10.1016/j.molstruc.2005.10.033