Mannich reaction

The Mannich reaction was named after his discovery of the mechanism in 1912.

The Mannich reaction is also considered a condensation reaction.

Progress has been made towards asymmetric Mannich reactions.

The Betti reaction is a special case of the Mannich reaction.

A Mannich reaction with formaldehyde and dimethylamine) produced gramine 4.

This reaction is described as an intramolecular "double Mannich reaction" for obvious reasons.

A related reaction is the Mannich reaction.

The Mannich reaction can proceed both intermolecularly and intramolecularly:

Like the Mannich reaction, aldehydes give good yields while ketones tend to give lower conversion.

The electrophilic partner is usually an aldehyde or ketone (many variations, such as the Mannich reaction, exist).

First step appears to be a Mannich reaction between acetophenone, paraformaldehyde and dimethylamine, although not formally written in the scheme.

Especially important is the so-called organocatalysis of organic reactions by proline for example in Mannich reactions.

Dopamine 1 then reacts with 4-hydroxy-phenylacetaldehyde 2 to form (S)-norcolaurine 3 in a reaction similar to the Mannich reaction.

In the Mannich reaction, ammonia or primary or secondary amines are employed for the activation of formaldehyde.

Gramine, a useful synthetic intermediate, is produced via a Mannich reaction of indole with dimethylamine and formaldehyde.

This is suitable for cleaving glycols and alpha-hydroxy ketones in ring opening and Mannich reaction.

The mechanism of the Petasis reaction is not fully understood; however, it is similar to the Mannich reaction at its early stage.

Mannich reaction (voacamine)

The mechanism of the Mannich reaction starts with the formation of an iminium ion from the amine and the formaldehyde.

Despite being widely available in several plant species, gramine is far easier to synthesize directly from indole via a Mannich reaction with dimethylamine and formaldehyde.

This can occur in a number of ways including reaction with ammonia or another amine such as an alkylation, reductive amination and the Mannich reaction.

The Mannich reaction is an example of nucleophilic addition of an amine to a carbonyl group followed by dehydration to the Schiff base.

The key step was an aza-Cope Mannich reaction initiated by an amine-carbonyl condensation using formaldehyde and forming 6 in a quantitative yield:

However, there are a few typical reactions involved in the biosynthesis of various classes of alkaloids, including synthesis of Schiff bases and Mannich reaction.