Furoin – preparation and application
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General description and preparation:
It can be produced from furfural via benzoin condensation in presence of cyanide ion or N-heterocyclic carbene catalyst as various thiazolium and imidazolium ions. They can be further supported as a recyclable precatalysts, which upon treatment with a base, catalyze furfural self-condensation coupling reaction into furoin.
Furoin synthesis from furfural is also catalyzed by vitamin B1 (thiamine). In 1957, Ronald Breslow proposed the mechanism of reaction that involves a relatively stable carbene form of thiamine, which was the first evidence for the existence of persistent carbenes.
Application of Furoin:
Furoin can be used in synthesis of pyrazine and quanoxiline derivatives by condensation with diamines. Different tetrasubstituted pyroles can be prepared from furoin as α-hydroxy ketone via a base-promoted three-component reaction with malononitrile and alcohols or 1,3-dicarbonyls and ammonium acetate.
Product categorization (Chemical groups):
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