نتایج جستجو برای: unsymmetrical ethers
تعداد نتایج: 8666 فیلتر نتایج به سال:
Ene-yne cross-metathesis from alkynes and ethylene is a useful method to produce substituted conjugated butadiene derivatives. If this method has been used with aliphatic alkynes, it has however never been used starting from diarylacetylenes as internal alkynes. We show that the ene-yne cross-metathesis catalyzed by the second generation Hoveyda ruthenium catalyst provides the 2,3-diarylbuta-1,...
We report the syntheses and properties of thienopyrrole based unsymmetrical and extended heteroacenes, which are isoelectronic with heptacene (30π) and nonacene (38π), respectively. Optical and electrochemical properties of these seven and nine rings fused systems are studied. The optoelectronic properties of the syn and anti-isomers of the unsymmetrical heteroacenes are also compared. The infl...
Sulfonyl oxime ethers undergo facile nucleophilic substitutions with various nucleophiles to yield the corresponding oxime ethers which provide an easy access to amines and carbonyl compounds.
Silicon and germanium containing pyridine aldoxime, ketoxime and amidoxime O-ethers have been prepared using phase transfer catalytic systems oxime alkyl halide solid KOH 18-crown-6 benzene and oxime alkyl halide solid K(2)CO(3) or Cs(2)CO(3) 18-crown-6 toluene. Cytotoxic activity of silicon and germanium containing pyridine oxime O-ethers was tested in vitro on two monolayer tumor cell lines: ...
catalytic amount of ce(iv) as ceric triethylammonium nitrate (ctean) in dichloromethane or acetone can bring about an efficient tetrahydropyranylation of different types of alcohols to afford the corrsesponding tetrahydropyranyl ethers in high yields. deportection of tetrahydropyranyl ethers can also be achieved efficiently in the presence of this catalyst in methanol.
Unified unsymmetrical and symmetrical iterative solvers for handling multiple right-hand-side vectors are examined in this work. Efficient computer implementation strategies (to reduce computational time and in-core memory requirements) are proposed. In-core, out-of-core, linear, multiple right hand side (RHS) vectors, non-linear, symmetrical, and unsymmetrical capabilities of the developed sof...
The potency of a series of Hexamethylene bis-acetamide (HMBA) derivatives inducing Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) was determined in LNCaP prostate cancer cells. Several compounds with unsymmetrical structures showed significantly improved activity. Distinct from HMBA, these analogs have increased hydrophobicity and can improve the short half-life of HMBA, which is one ...
Positive-sequence virtual-flux control of grid-connected converter during unsymmetrical voltage dips
One of the major problems in direct power-controlled grid-connected voltage source converters is that during dips, converter current increases to compensate for reduced grid voltage. The most common dips are unsymmetrical, and they cause unbalance distortion current. This paper introduces a new, simple but effective algorithm which limits dips. A positive-sequence virtual-flux based control sch...
We prepared a significant number of unsymmetrical liquid-crystalline dimers that exhibit the twist-bend nematic phase; a state of matter that exhibits spontaneous breaking of mirror symmetry and, for some materials, a microsecond electrooptic response. A number of novel unsymmetrical bimesogens were synthesized and in comparing their thermal behaviour to previous literature examples, we have un...
Thirty-six halogenated Me Et ethers have been synthesized for evaluation as volatile anesthetics. Eleven of the ethers were too unstable to test, and, of the remaining 25, 13 had promising anesthetic properties in mice and are suitable for study in larger animals. Those ethers having one H with at least 2 halogens other than F or 2 or more H with at least one Br or Cl were the best anesthetics.
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