The Knoevenagel condensation reaction is a Organic reactions are chemical reactions between organic compounds. ...organic reaction named after Heinrich Emil Albert Knoevenagel ( 18 June 1865 _ 11 August 1921) was the German chemist who established the Knoevenagel condensation reaction. The Knoevenagel condensation reaction of benzaldehydes with nitroalkanes is a classic general method for the preparation of nitroalkenes, which are very valuable synthetic intermediates. ...Emil Knoevenagel. It is a modification of the An aldol reaction takes the following form: 2 enolate anions ↔ aldol The reaction requires a base catalyst. ...Aldol condensation.

A Knoevenagel condensation is a Nucleophilic addition involves the addition of a nucleophile to a chemical compound. ...nucleophilic addition of a active hydrogen compound to a In chemistry, a carbonyl group is a functional group composed of an atom of carbon double-bonded to an atom of oxygen. ...carbonyl group followed by a An elimination reaction is a type of organic chemical reaction in which two groups are removed from a molecule in either a one or two_step mechanism. ...elimination reaction in which a molecule of water is lost (hence condensation). The product is a alpha,beta A chemically conjugated system, is a system of atoms covalently bonded with alternating single and double bonds (e. ...conjugated enone.

In this reaction the carbonyl group is an An aldehyde is either a functional group consisting of a terminal carbonyl group, or a compound containing a terminal carbonyl group. ...aldehyde or a A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ...ketone.The A catalyst (Greek: καταλύτης) is a substance that accelerates the rate of a chemical reaction, at some temperature, but without itself being transformed or consumed by the reaction (see also catalysis). ...catalyst is usually an weakly The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ...basic Ammonia Amines are organic compounds containing nitrogen as the key atom in the amine functional group. ...amine. The active hydrogen component has the form

• Z_CH₂_Z or Z_CHR_Z for instance Diethyl malonate (DEM) has the structure (EtOOC)(CH2)(COOEt) Reactions Malonic ester synthesis DEM → monosubstituded acetic acid See also barbituric acid ...diethyl malonate or Malonic acid is the bi_carboxylic acid with structure CH2(COOH)2. ...malonic acid.
• Z_CHR₁R₂ for instance Nitromethane is a fuel that is used in racing, particularly in drag racing, to provide more power. ...nitromethane.

where Z is an electron withdrawing In ecology functional groups are collections of organisms based on morphological, physiological, behavioral, biochemical, or environmental responses or on trophic criteria. ...functional group. Z must be powerfull enough to facilitate hydrogen abstraction to the enolate ion even with a mild base. Using a strong base in this reaction would induce self-condensation of the aldehyde or ketone.

With malonic compounds the reaction product can lose a molecule of Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ...carbon dioxide in a subsequent step.

Example reactions

A Knoevenagel condensation is demonstrated in the reaction of 2-methoxybenzaldehyde 1 with N,N-diethylthio barbituric acid 2 in Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ...ethanol using Categories: Chemistry stubs ...piperidine as a base ^[1]. The resulting enone 3 is a A charge transfer complex is defined over a pair of a molecular groups, where one is electron donating and the other is electron accepting, where there is a partial transfer of electronic charge from the acceptor to the donor in an excited molecular state(excited state). ...charge transfer complex molecule.

References

• ^[1] 1,3-Diethyl-5-(2-methoxybenzylidene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione Abdullah Mohamed Asiria, Khaled Ahmed Alamrya Abraham F. Jalboutb, Suhong Zhang Molbank 2004, M359 [1]  (http://www.mdpi.net/molbank/molbank2004/m0359.htm) The open access movement (also known as open-access publishing and free online scholarship) is an effort to grant access to a large variety of up-to-date information sources for free. ...open access publication.