Claisen - Schmidt condensation

Explanation

It involves the condensation between an aromatic aldehyde (or a ketone) with an aliphatic aldehyde or a ketone in presence of dilute alkali to form `alpha, beta`- unsaturated compounds.
For example,

In presence of excess benzaldehyde, the benzalacetone thus formed reacts further with another molecule of benzaldehyde to form dibenzalacetone. Thus,

Similarly, acetophenone condeness with benzaldehyde in presence of dilute alkali to form benzalacetophenone or phenyl styryl ketone

Such `alpha,beta`- unsaturated compounds are also called chalcones.