A new way for synthetizing (E)-methyl methylsulfanyl(phenylamino)methylene carbamates via Beckmann transposition in triflic acid

Abstract

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.

Keywords

• Nitroketene S
• N-acetals
• Electrophilic aromatic substitution
• Superacids
• Triflic acid
• Beckmann transposition