Amine Carbonyl Reaction Mechanism

Reaction of Amine with Carbonyl compunds

Only primary amines react with aldehydes and ketones and condensation products are obtained. These condensation products are known as imines or Schiffs bases.

R-CHO (aldehyde) + RNH2  ---------> RCH = N-R (aldimine)

R2CO (ketone) + R-NH2 --------> R2C = N-R (ketimines)

Imines can be reduced to secondary amines. This reaction, in turn, can be used to convert a primary amine to secondary amine.

RCH = NR  ------(H2 / Ni)-----> R-CH2-NH-R  (Secondary amine)

R2C = N-R ------(H2 / Ni)-----> R2CH-NH-R

For more visit Properties of Amines

acylation of amines

Acylation of amines mechanism

Both aliphatic and aromatic primary and secondary amines undergo N-acetylation. This acetylation can be effected using acid halides or anhydrides in presence of a base (pyridine) and the product obtained is an amide. Base remove HCl and prevent protonation of amine.

primary amine acylation
Acylation of primary amine

Secondary amine acylation
Acylation of Secondary amine

Since amides formed are not basic, they do not under go further actylation. Acid chlorides are stronger acetylating agent than acetic anhydride.
In tertiary amines there is no replaceable hydrogen and they do not undergo acylation.