What is Knoevenagel reaction mechanism?
The Knoevenagel reaction is a modified Aldol Condensation with a nucleophilic addition between an aldehyde or ketone, and an active hydrogen compound in the presence of a basic catalyst, resulting in C–C bond formation. The reaction is usually followed by spontaneous dehydration resulting in an unsaturated product.
What is Stobbe condensation reaction?
Stobbe condensation involves reaction of aldehyde or ketone with succinic ester in the presence of basic catalyst like sodium hydroxide or potassium tertiary butoxide to form alkylidene succinic acid. • This reaction limited to α – ω diester ester group at 1st carbon and last carbon.
What base is Knoevenagel reaction?
Knoevenagel condensation (Scheme 1) is a widely used reaction in research and industry and has been of importance for several pharmaceutical products. Generally this reaction is catalyzed by organo-bases, such as pyridine or piperidine.
What catalyst is used in Knoevenagel reaction?
Sakaiused Indium (III) Chloride as a catalyst in reaction of acetic anhydride and aldehyde which is followed by Knoevenagel reaction.
Is knoevenagel condensation reversible?
These results further indicate that this CKC reaction is a reversible reaction, and the increase in reactant concentrations can promote the forward reaction.
Who discovered Knoevenagel reaction?
In 1894, German chemist Emil Knoevenagel reported that diethyl malonate and formaldehyde condensed in the presence of diethylamine to form a bis adduct.
What are aldol condensation reactions?
In an aldol condensation, an enolate ion reacts with a carbonyl compound in the presence of acid/base catalyst to form a β-hydroxy aldehyde or β-hydroxy ketone, followed by dehydration to give a conjugated enone. It is a useful carbon-carbon bond-forming reaction.
Which is the primary product formed in Stobbe condensation?
One mole of metal alkoxide is required per mole of carbonyl compound and ester, and the primary product is the salt of the half-ester.
What is product of knoevenagel condensation?
A Knoevenagel condensation is a nucleophilic addition of an active hydrogen compound to a carbonyl group followed by a dehydration reaction in which a molecule of water is eliminated (hence condensation). The product is often an α,β-unsaturated ketone (a conjugated enone).
What is condensation mechanism?
From Wikipedia, the free encyclopedia. In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a dehydration synthesis.
What is the product of knoevenagel condensation?
Which is the final product of Stobbe condensation?
B.v The Stobbe Condensation. Condensation of succinic ester derivatives (such as diethyl succinate, 232) with non-enolizable ketones or aldehydes and a base gives the condensation product 233. The alkoxide reacts with the distal ester via acyl substitution to give a lactone intermediate (234).