Transamidation

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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 typically very slow, but it can be accelerated with Lewis acid[1] and organometallic catalysts.[2] 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:[3]

(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:[4]

(H2N)2CO + [C6H5NH3]Cl → (C6H5(H)N)(H2N)CO + NH4Cl

Hydrazine derivatives of urea are often produced by transamidation-like reactions. These products include carbohydrazide, semicarbazide, and biurea.

References[]

  1. ^ T. A. Dineen, M. A. Zajac, A. G. Myers (2006). "Efficient Transamidation of Primary Carboxamides by in situ Activation with N,N-Dialkylformamide Dimethyl Acetals". J. Am. Chem. Soc. 128 (50): 16406–16409. doi:10.1021/ja066728i. PMID 17165798.CS1 maint: uses authors parameter (link)
  2. ^ Emma L. Baker, Michael M. Yamano, Yujing Zhou, Sarah M. Anthony, Neil K. Garg (2016). "A two-step approach to achieve secondary amide transamidation enabled by nickel catalysis". Nature Communications. 7: 11554. Bibcode:2016NatCo...711554B. doi:10.1038/ncomms11554. PMC 4876455. PMID 27199089.CS1 maint: uses authors parameter (link)
  3. ^ C. Nitschke; G. Scherr (2012). "Urea Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.o27_o04.
  4. ^ "Arylureas II. Urea Method p-Ethoxyphenylurea". Org. Synth. 31: 11. 1951. doi:10.15227/orgsyn.031.0011.
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