نتایج جستجو برای: benzoin
تعداد نتایج: 326 فیلتر نتایج به سال:
Fluorinated and nonfluorinated phosphonates are employed as precatalysts in lithium phosphonate catalyzed cross benzoin couplings. Surprisingly, a decreased catalytic activity for the fluorinated precatalysts compared to the nonfluorinated systems is observed. Furthermore, the ring size of six, seven and nine membered ring catalysts appears not to be crucial for their catalytic activity.
A chemo- and enantioselective cross-aza-benzoin reaction between enals and isatin-derived ketimines is disclosed. The high chemoselectivity (of the acyl anion reaction over enal α- and β-carbon reactions) is enabled by the electronic and steric properties of the N-heterocyclic carbene organocatalyst.
A tandem NHC-catalyzed aza-benzoin/Michael reaction has been developed as a method to efficiently produce dihydroindenones and pyrrolidinone-containing tricycles. The novel reaction pattern involves tert-butyl aryl(tosyl)methylcarbamates reacting as both electrophile and nucleophile on the same carbon.
to disappear completely. (d) Gentle massage is very essential after injection. (?) Too strong a solution gives pain. I always inject 5 grs. in 20 minims of distilled water. If this dose is not sufficient, it may be repeated. Whenever I used a stronger solution it invariably gave a certain amount of pain(/) The puncture should be sealed with compound benzoin tincture or collodiuin flexile. Simpl...
The purpose of this work was to quantify the variation of subcanopy spatiotemporal light dynamics over the course of a year and to link it to the physiological ecology of the understory shrub, Lindera benzoin L. Blume (northern spicebush). Covering all seven phenoseasons of a deciduous forest, this work utilized a line quantum sensor to measure the variation in subcanopy light levels under all ...
An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure....
Rate and equilibrium constants for the reaction between N-aryl triazolium N-heterocyclic carbene (NHC) precatalysts and substituted benzaldehyde derivatives to form 3-(hydroxybenzyl)azolium adducts under both catalytic and stoichiometric conditions have been measured. Kinetic analysis and reaction profile fitting of both the forward and reverse reactions, plus onwards reaction to the Breslow in...
Occlusion of the healthy eye is the mainstay of amblyopia treatment. Occlusion therapy has practical limitations; many children actively resist treatment and some parents are marginally compliant with instructions. Even when parents are knowledgeable about amblyopia and patching, 22% report poor compliance. Strategies such as atropine, hand socks, inflatable water wings, benzoin tincture, occlu...
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