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The benzilic acid rearrangement is formally the 1,2-rearrangement of 1,2-diketones to form α-hydroxy–carboxylic acids using a base. This reaction receives its name from the reaction of benzil with potassium hydroxide to form benzilic acid. First performed by Justus von Liebig in 1838, [1] it is the first reported example of a rearrangement ...
A classic organic reaction of benzil is the benzilic acid rearrangement, in which base catalyses the conversion of benzil to benzilic acid. This reactivity is exploited in the preparation of the drug phenytoin. Benzil also reacts with 1,3-diphenylacetone in an aldol condensation to give tetraphenylcyclopentadienone.
An example of a less common radical 1,2-shift can be found in the gas phase pyrolysis of certain polycyclic aromatic compounds. [4] The energy required in an aryl radical for the 1,2-shift can be high (up to 60 kcal / mol or 250 kJ /mol) but much less than that required for a proton abstraction to an aryne (82 kcal/mol or 340 kJ/mol).
Benzilic acid can be prepared by heating a mixture of benzil, ethanol, and potassium hydroxide. Another preparation, performed by Liebig in 1838, is the dimerization of benzaldehyde , to benzil , which is transformed to the product by the benzilic acid rearrangement reaction.
In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. [1] Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular. In the example below ...
In his second publication in 1860 he reacted paraceton with sulfuric acid (the actual pinacol rearrangement). Again Fittig was unable to assign a molecular structure to the reaction product which he assumed to be another isomer or a polymer. Contemporary chemists who had already adapted to the new atomic weight reality did not fare better.
Benzilic acid rearrangement; Benzoin condensation; Bergman cyclization; Bergmann azlactone peptide synthesis; Bergmann degradation; Bergmann–Zervas carbobenzoxy method; Bernthsen acridine synthesis; Bestmann's reagent; Betti reaction; Biginelli pyrimidine synthesis; Biginelli reaction; Bingel reaction; Birch reduction; Bischler–Möhlau ...
In organic chemistry, a cross-coupling reaction is a reaction where two different fragments are joined. Cross-couplings are a subset of the more general coupling reactions. Often cross-coupling reactions require metal catalysts. One important reaction type is this: