knoevenagel condensation

The first step in the ring synthesis is related to the Knoevenagel condensation.

The mechanism operates in same way as the Knoevenagel condensation:

The reaction is especially common in conjunction with the malonic ester synthesis and Knoevenagel condensations.

First, acrolein is formed in a Knoevenagel condensation from the acetaldehyde and formaldehyde.

Pyridine is used as polar, basic, low-reactive solvent, for example in Knoevenagel condensations.

The first step is a Knoevenagel condensation between the ketone (1) and the α-cyanoester (2) to produce the stable intermediate 3.

As an example, an enone such as a chalcone can be synthesized in a Knoevenagel condensation.

Using the Knoevenagel condensation reaction, barbituric acid can form a large variety of barbiturate drugs that behave as central nervous system depressants.

CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation:

Although β-nitrostyrene is commercially available, it is also very easily prepared using the Knoevenagel condensation between benzaldehyde and nitromethane.

A Knoevenagel condensation is demonstrated in the reaction of 2-methoxybenzaldehyde 1 with the barbituric acid 2 in ethanol using piperidine as a base.

The researchers showed that the amides are capable of base-catalyzing the Knoevenagel condensation of benzaldehyde with malononitrile.

This allows it to be used in the Knoevenagel condensation, for example in the preparation of CS gas:

The Knoevenagel condensation reaction is an organic reaction named after Emil Knoevenagel.

When the base is an amine and the active hydrogen compound is sufficiently activated the reaction is called a Knoevenagel condensation.

The Knoevenagel condensation is a key step in the commercial production of the antimalarial drug lumefantrine (a component of Coartem):

Because of its great acidity, Meldrum's acid, like malonic acid, can serve as a reactant in Knoevenagel condensations.

The Knoevenagel condensation reaction of benzaldehydes with nitroalkanes is a classic general method for the preparation of nitroalkenes, which are very valuable synthetic intermediates.

PPV derivatives can be also produced via the Knoevenagel condensation between a benzylic nitrile and an aromatic dialdehyde.

The carbanion forms by proton abstraction of the acidic α-proton by pyridine (now serving a double role) akin to the Knoevenagel condensation.

Malonic acid is also frequently used as an enolate in Knoevenagel condensations or condensed with acetone to form Meldrum's acid.

CsF gives higher yields in Knoevenagel condensation reactions than KF or NaF.

Condensation of cyclopentanone with cyanoacetic acid in a modified Knoevenagel condensation followed by decarboxylation affords the unsatured nitrile.

The free non-coordinated ends of the ethylenediamines were then used as Brøsted basic catalysts, again for Knoevenagel condensation of benzaldehyde with nitriles.

The first step is a Knoevenagel condensation between the barbituric acid and the aldehyde, the second step is a reverse electron-demand Diels-Alder reaction.