A new way for synthetizing (E)-methyl methylsulfanyl(phenylamino)methylene carbamates via Beckmann transposition in triflic acid
At low temperature in triflic acid, nitroketene S,N-acetals with a tethered phenyl ring react to form the corresponding hydroxynitrilium ions. Quenching with methanol leads to the formation of dications which undergo an unexpected Beckmann transposition affording new (E)-methyl methylsulfanyl(phenylamino) methylene carbamates.
KEY WORDS: Nitroketene S,N-acetals, Electrophilic aromatic substitution, Superacids, Triflic acid, Beckmann transposition
Bull. Chem. Soc. Ethiop. 2015, 29(2), 291-298