The Ritter reaction uses a strong protic acid and water or a solvent to convert a nitrile and a carbocation precursor molecule to an amide product. First the precursor molecule becomes a carbocation, which is attacked by the nitrogen atom of the nitrile to form a nitrilium ion. An imidate is then formed when the conjugate base of the acid (hydrogen sulfate anion in this case) adds to the nitrilium ion. Hydrolysis produces the desired N-substituted amide product.

• The alcohol or alkene is usually added to the nitrile substrate (classically dissolved in a mixture of acetic acid and concentrated sulfuric acid) at slightly elevated temperatures (50 – 100°C).
• Lewis Acids such as SnCl₄, AlCl₃, etc. can also be employed to generate the required carbocation.
• Besides aliphatic and aromatic nitriles, cyanogen and cyanamide are also substrates.
• The initial carbocation may undergo a Wagner-Meerwein rearrangement to generate the most stable carbocation before reacting with the nitrile.
• 1,1-disubstituted alkenes give rise to regioisomerically pure products, while 1,2-disubstituted alkenes may form a mixture of regioisomers.

• Reagents: Strong Protic Acid (H₂SO₄, HClO₄, HCO₂H, etc.), H₂O or Solvent (Acetic Acid, H₂SO₄ (conc.), CHCl₃, etc.)
• Reactant: Aliphatic or Aromatic Nitrile, Carbocation Precursor (Alkene, Alkyl Halide, 2°, 3° or Benzylic Alcohol)
• Product: N-Substituted Amides
• Type of Reaction: Addition
• Bond Formation: N-C, N-H, C-C, C=O

Mechanism

Original Paper

Top Citations

Related Reactions

Related Compounds