A facile and general synthesis of various N-substituted cyanamides was accomplished by the Tiemann rearrangement of amidoximes with benzenesulfonyl chlorides (TsCl or o-NsCl) and DIPEA.

CuI-Catalyzed intramolecular aminocyanation of terminal alkynes in N-(2-ethynylphenyl)-N-sulfonylcyanamides was initiated by the formation of Cu-acetylide to trigger N-CN bond cleavage of the N-sulfonylcyanamide moiety followed by CN migration to form a β-cyano Cu-vinylidene intermediate. Subsequently, the indole ring closure furnished the corresponding 1-sulfonyl-3-cyanoindoles.

The reaction of methyl anthranilates with N-arylcyanamides in the presence of p-TsOH in t-BuOH under reflux afforded predominantly 3-arylquinazolin-4-ones. In contrast, the reaction of the same reactants with TMSCl in t-BuOH at 60 °C followed by the Dimroth rearrangement in aqueous ethanolic sodium hydroxide gave exclusively the regioisomers, 2-(N-arylamino)quinazolin-4-ones. The regioselective synthesis of N-aryl-substituted 2-aminoquinazolin-4-ones can be further applied to the synthesis of benzimidazo[2,1-b]quinazolin-12-ones.

Two different reaction pathways were observed in the sulfonylation of N-phenylbenzamidoximes. The reaction with o-NsCl at a heating temperature gave N,N 0 -diphenylureas via Tiemann rearrangement, while the reaction with Ts 2 O at a lower temperature formed 2-phenylbenzimidazoles via intramolecular electrophilic aromatic substitution. When the amide nitrogen was replaced with carbon substituents, oxime derivatives of benzoins and benzils underwent Beckmann fragmentation reactions upon sulfonylation, whereas sulfonylation of 2-phenylacetophenone oxime afforded exclusively the Beckmann rearrangement adduct.