Question

Which base is use in Knovengel reaction ?​

Answer 1

Answer:

A Knoevenagel condensation is demonstrated in the reaction of 2-methoxybenzaldehyde 1 with the thiobarbituric acid 2 in ethanol using piperidine as a base. The resulting enone 3 is a charge transfer complex

Answer 2

Amine base is used as a catalyst in the Knoevenagel reaction.

• The Knoevenagel condensation is an organic reaction that converts a carbonyl functional group (aldehyde or ketone) and activated methylene (esters) into a substituted olefin (alkene).
• An amine base is used as a catalyst. It is not consumed during the reaction and it speeds up the reaction rate.
• The amine catalyst reacts with the aldehyde or ketone to form an iminium ion intermediate.
• The intermediate then gets attacked by the enolate and gets deprotonated by the base.
• Rearrangement happens that gives the final product and the base is released.