Illustrated Glossary of Organic Chemistry

Mannich reaction: A reaction in which a CH₂NR₂ group is added to a carbonyl α-carbon (via the corresponding enolate or enol). The CH₂ is provided by formaldehyde, and the NR₂ by ammonia, a primary amine, or a secondary amine.

General form of the Mannich reaction.

	+		+
Acetophenone		1,3,5-Trioxane		Dimethylammonium chloride		Mannich product

In this Mannich reaction example, acetophenone is reacted with 1,3,5-trioxane (a formaldehyde trimer) and dimethylammonium chloride in acidic ethanol to give the Mannich product.