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The Wheland intermediate is the name typically given to the cationic reactive intermediate formed in electrophilic aromatic substitution, and can be considered an oppositely charged analog of the negatively charged Meisenheimer complex formed in nucleophilic aromatic substitution. Hence, the simultaneous occurrence of the Wheland and ...
Other alkali metals can be used in place of sodium, and most alcohols can be used in place of methanol. Generally, the alcohol is used in excess and left to be used as a solvent in the reaction. Thus, an alcoholic solution of the alkali alkoxide is used. Another similar reaction occurs when an alcohol is reacted with a metal hydride such as NaH.
Methoxymethanol forms spontaneously when a water solution of formaldehyde and methanol are mixed. [3] [1] or when formaldehyde is bubbled through methanol. [4] In space methoxymethanol can form when methanol radicals (CH 2 OH or CH 3 O) react. These are radiolysis products derived when ultraviolet light or cosmic rays hit frozen methanol. [3]
A tetrahedral intermediate is a reaction intermediate in which the bond arrangement around an initially double-bonded carbon atom has been transformed from trigonal to tetrahedral. [1] Tetrahedral intermediates result from nucleophilic addition to a carbonyl group.
Methanol and its vapours are flammable. Moderately toxic for small animals – Highly toxic to large animals and humans (in high concentrations) – May be fatal/lethal or cause blindness and damage to the liver, kidneys, and heart if swallowed – Toxicity effects from repeated over exposure have an accumulative effect on the central nervous system, especially the optic nerve – Symptoms may ...
For lithium-free Wittig reactions, studies support a concerted formation of the oxaphosphetane without intervention of a betaine. In particular, phosphonium ylides 1 react with carbonyl compounds 2 via a [2+2] cycloaddition that is sometimes described as having [ π 2 s + π 2 a ] topology to directly form the oxaphosphetanes 4a and 4b .
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Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. [3] Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one ...