In chemistry, a multi component reaction (or MCR) is a chemical reaction where three or more compounds react to form a single product.^[1] Chemistry (derived from the Arabic word kimia, alchemy, where al is Arabic for the) is the science that deals with the properties of organic and inorganic substances and their interactions with other organic and inorganic substances. ... A chemical reaction is a process that results in the interconversion of chemical substances . ... A compound is an area of land that is surrounded by fences, walls, or barbed wire and is used for a particular purpose, especially an area containing buildings and where the entry and exit of people is controlled. ...

Examples of three component reactions:

• Alkyne trimerisation
• Biginelli reaction
• Bucherer-Bergs reaction
• Gewald reaction
• Hantzsch pyridine synthesis
• Kabachnik-Fields Reaction
• Mannich reaction
• Passerini reaction
• Pauson-Khand reaction
• Strecker amino acid synthesis

Examples of four component reactions: A alkyne trimerisation reaction is a [2+2+2] cyclization reaction where three alkyne molecules react to form a benzene compound. ... The Biginelli reaction is a multiple-component chemical reaction that creates 3,4-dihydropyrimidin-2(1H)-ones 4 from ethyl acetoacetate 1, an aryl aldehyde (such as benzaldehyde 2), and urea 3. ... The Gewald reaction is a chemical reaction involving the condensation of a ketone (or aldehyde when R2 = H) with a α-cyanoester in the presence of elemental sulfur to give a tetra-substituted thiophene. ... The Hantzsch pyridine synthesis or Hantzsch dihydropyridine synthesis is a multi component organic reaction between an aldehyde such as formaldehyde, 2 equivalents of a β-keto ester such as ethyl acetoacetate and a nitrogen donor such as ammonium acetate or ammonia . ... The Mannich reaction is a chemical reaction in organic chemistry and is a amino alkylation of an acidic proton placed next to a carbonyl functional group with formaldehyde and ammonia or any primary or secondary amine. ... The Passerini reaction is a chemical reaction involving an isocyanide, an aldehyde (or ketone), and a carboxylic acid to form a α-acyloxy amide. ... The Pauson–Khand reaction or PKR or PK-type reaction is a [2+2+1] cycloaddition between an alkyne, an alkene and carbon monoxide to form a α,β-cyclopentenone . ... The Strecker amino acid synthesis is a series of chemical reactions the synthesize an amino acid from an aldehyde. ...

• Ugi reaction
• Asinger reaction

The exact nature of this type of reaction is often difficult to assess, in collision theory a simultaneous interaction of 3 or more different molecules is less likely resulting in a low reaction rate. These reactions are more likely to involve a series of bimolecular reactions. The Ugi reaction is a multi component reaction in organic chemistry involving a ketone or aldehyde, an amine, a isocyanide and a carboxylic acid to form a bis-amide. ... The reaction rate for a reactant or product in a particular reaction is defined as the amount (in moles or mass units) per unit time per unit volume that is formed or removed. ...

New MCR's are found by building a chemical library from combinatorial chemistry or by combining existing MCR's.^[2] For example, a 7-component MCR results from combining the Ugi reaction with the Asinger reaction.^[3] MCR's are an important tool in new drug discovery. Combinatorial chemistry involves the rapid synthesis and/or the computer simulation of a large number of different but structurally related molecules. ... The Ugi reaction is a multi component reaction in organic chemistry involving a ketone or aldehyde, an amine, a isocyanide and a carboxylic acid to form a bis-amide. ...

See also

• A tandem reaction is a consecutive series of intramolecular organic reactions.

Intramolecular describes a process or characteristic limited within the structure of a single, or each molecule; a property or phenomenon limited to the extent of a single, or each molecule. ... Organic reactions are chemical reactions between organic compounds. ...

References

1. ^  Armstrong, R. W.; Combs, A. P.; Tempest, P. A.; Brown, S. D.; Keating, T. A. Acc. Chem. Res. 1996, 29, 123-131.
2. ^  Recent progress in the chemistry of multicomponent reactions Ivar Ugi Pure Appl. Chem. 2001, 73, 187-191. (Online article)
3. ^  The discovery of new isocyanide-based multi-component reactions Alexander Dömling Current Opinion in Chemical Biology 2000, 4, 318-323. (Online article)

External link

• Multicomponent reactions