Information om | Engelska ordet ALKOXIDE

Exempel på hur man kan använda ALKOXIDE i en mening

• A transition metal alkoxide complex is a kind of coordination complex containing one or more alkoxide ligands, written as , where R is the organic substituent.
• For example, deprotonation of an alcohol forms the negatively charged alkoxide, which is a much stronger nucleophile.
• The rate determining step of the reaction is de-protonation of the hydrazone by an alkoxide base to form a diimide anion by a concerted, solvent mediated protonation/de-protonation step.
• Often, as in conventional Claisen condensations, Mannich reactions, and aldol condensations, enolates are generated in low concentrations with alkoxide bases.
• In the presence of a very high concentration of base, the aldehyde first forms a doubly charged anion from which a hydride ion is transferred to the second molecule of aldehyde to form carboxylate and alkoxide ions.
• The reaction of allyl phenyl ether 1 with sec-butyllithium at −78 °C gives the lithiated intermediate 2 which on heating to −25 °C only shows the rearranged product 5 but not 4 after trapping the lithium alkoxide with trimethylsilyl chloride.
• Schrock catalysts feature molybdenum(VI)- and tungsten(VI)-based centers supported by alkoxide and imido ligands.
• The resulting β-nitro alkoxide is protonated by the conjugate acid of the base that originally deprotonated the nitroalkyl structure, giving the respective β-nitro alcohol as product.
• Carboxylic acids easily dissociate into a carboxylate anion and a positively charged hydrogen ion (proton), much more readily than alcohols do (into an alkoxide ion and a proton), because the carboxylate ion is stabilized by resonance.
• Williamson is credited for his research on the formation of unsymmetrical ethers by the interaction of an alkoxide with a haloalkane, known as the Williamson ether synthesis.
• Examples may include hydronium and hydroxide ions in water and water alcohol mixtures, alkoxonium and alkoxide ions in the same mixtures, ammonium and amide ions in liquid and supercritical ammonia, alkylammonium and alkylamide ions in ammines mixtures, etc.
• The dithiophosphine ylides are normally attacked at the phosphorus atom by a nucleophile, for instance the reaction of an alkoxide, phenolate, alcohol or phenol with a 1,3,2,4-dithiadiphosphetane 2,4-disulfide can form a new compound with a phosphorus-oxygen bond.
• The negative charge carried by the nucleophile is now delocalized in the alkoxide anion and the α carbon carbanion by resonance.
• The order of reactivity of alkoxides, K > Na >> Mg, is consistent with higher electron density on oxygen, hence increasing the alkoxide nucleophilicity.
• The cationic species then dealkylates through a second nucleophilic displacement in which the halide anion attacks one of the phosphite alkoxide substituents forming an enol phosphate.
• The alkoxide used should not be easily oxidizable (such as potassium ethoxide) as this favors the Meerwein–Ponndorf–Verley reduction pathway as a side reaction.
• The Gabriel–Colman rearrangement is the chemical reaction of a saccharin or phthalimido ester with a strong base, such as an alkoxide, to form substituted isoquinolines.
• Alkylation of the alkoxide from that alcohol with p-chlorobenzyl chloride leads to econazole (5); alkylation with o,p-dichlorobenzyl chloride gives miconazole.
• An oxyanion hole is a pocket in the active site of an enzyme that stabilizes transition state negative charge on a deprotonated oxygen or alkoxide.
• The reaction of the benzothiazole sulfone (1) with lithium diisopropylamide (LDA) gives a metallated benzothiazolyl sulfone, which reacts quickly with aldehydes (or ketones) to give an alkoxide intermediate (2).

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