Transamidation is a chemical reaction in which an
amide reacts with an
amine to generate a new amide:
- RC(O)NR'2 + HNR"2 → RC(O)NR"2 + HNR'2
The reaction is rarely employed, but it could prove relevant to peptide synthesis.
Amides are characteristically inert, but the amino substituents can be exchanged in the presence of Lewis acid and organometallic . Primary amides (RC(O)NH2) are more amenable to this reaction.
Ureas
In contrast to the reluctance of amides as substrates,
urea is more susceptible to this exchange process. Transamidation is practiced, sometimes even on an industrial scale, to prepare a variety of N-substituted
ureas:
- (H2N)2CO + R2NH → (R2N)(H2N)CO + NH3
- (R2N)(H2N)CO + R2NH → (R2N)2CO + NH3
Methylurea, precursor to
theobromine, is produced from
methylamine and urea. Phenylurea is produced similarly but from anilinium chloride:
- (H2N)2CO + C6H5NH3Cl → (C6H5(H)N)(H2N)CO + NH4Cl
Hydrazine derivatives of urea are often produced by transamidation-like reactions. These products include carbohydrazide, semicarbazide, and biurea.
Further reading