In
organic synthesis
Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...
the Béchamp reaction is used for producing
arsonic acids from activated aromatic substrates. The reaction is an
electrophilic aromatic substitution
Electrophilic aromatic substitution (SEAr) is an organic reaction in which an atom that is attached to an aromatic ring, aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitut ...
, using
arsenic acid
Arsenic acid or arsoric acid is the chemical compound with the chemical formula, formula . More descriptively written as , this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic ...
as the electrophile. The reaction proceeds according to this idealized stoichiometry for the preparation of
arsanilic acid:
:
Reaction scope
The reaction was first reported in 1863 by
Antoine Béchamp. It is very analogous to the
sulfonation
In organic chemistry, aromatic sulfonation is a reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid () group. Together with nitration and chlorination, aromatic sulfonation is a widely used electrophilic aromatic substi ...
of arenes.
The Béchamp reaction was employed in the
Nobel Prize
The Nobel Prizes ( ; ; ) are awards administered by the Nobel Foundation and granted in accordance with the principle of "for the greatest benefit to humankind". The prizes were first awarded in 1901, marking the fifth anniversary of Alfred N ...
-winning work on
organoarsenicals by Paul Erlich.
In one commercial application, the Béchamp reaction is reaction is used to produce
roxarsone, which exhibits an
anticoccidial action and promotes growth in animals.
Further reading
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References
{{Organic reactions
Substitution reactions
Name reactions