Furoin or 1,2-di-2-hydroxyethanone is an organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 with formula C₁₀H₈O₄. It can be produced from furfural

Furfural

Furfural is an organic compound derived from a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word , meaning bran, referring to its usual source....

 by the catalytic

Catalysis

Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 action of cyanide

Cyanide

A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....

 ions.

Reactions

Furoin synthesis from furfural is also catalyzed by vitamin B₁ (thiamine). In 1957, R. Breslow

Ronald Breslow

Ronald C. D. Breslow is an American chemist from Rahway, New Jersey. He is currently University Professor at Columbia University, where he is based in the Department of Chemistry and affiliated with the Departments of Biological Sciences and Pharmacology; he has also been on the faculty of its...

 proposed that this reaction involves a relatively stable carbene

Carbene

In chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is RR'C:, but the carbon can instead be double-bonded to one group. The term "carbene" may also merely refer to the compound H2C:, also called...

 form of thiamine: In the catalytic cycle

Catalytic cycle

A catalytic cycle in chemistry is a term for a multistep reaction mechanism that involves a catalyst . The catalytic cycle is the main method for describing the role of catalysts in biochemistry, organometallic chemistry, materials science, etc. Often such cycles show the conversion of a...

 shown below two molecules of furfural react to give furoin, via a thiazol-2-ylidene catalyst, resulting from loss of one proton

Proton

The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

 at carbon 2 of the thiazolium cation of vitamin B₁:

This was the first evidence for the existence of persistent carbene

Persistent carbene

A persistent carbene is a type of carbene demonstrating particular stability. The best-known examples are diaminocarbenes with the general formula 2C:, where the 'R's are various functional groups...

s.