Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes.

The synthesis of zwitterionic dithiocarboxylate adducts was achieved by deprotonating various aldiminium or 1,2,3-triazolium salts with a strong base, followed by the nucleophilic addition of the in situ-generated cyclic (alkyl)(amino) or mesoionic carbenes (CAACs or MICs) onto carbon disulfide. Nine novel compounds were isolated and fully characterized by H and C NMR, FTIR, and HRMS techniques. Moreover, the molecular structures of two CAAC·CS and two MIC·CS betaines were determined by X-ray diffraction analysis.

The Facile Hydrolysis of Imidazolinium Chlorides (N-Heterocyclic Carbene Precursors) Under Basic Aqueous Conditions.

The hydrolysis of imidazolinium chlorides takes place readily in a basic water/dichloromethane biphasic mixture at room temperature. Experimental parameters were optimized to afford full conversions and high yields of γ-aminoformamides starting from twelve symmetrical substrates with alkyl or aryl substituents on their nitrogen atoms, and five unsymmetrical 1-alkyl-3-arylimidazolinium chlorides. NMR and XRD analyses showed that the cleavage of unsymmetrical salts led to γ-alkylamino-N-arylformamides with a high regioselectivity and that bulky alkyl or aryl groups on the formamide moiety led to the isolation of the (E)-isomer in high stereoisomeric purity (>95 %), whereas smaller and more flexible alkyl substituents afforded mixtures of (E)- and (Z)-rotamers.

Efficient N-heterocyclic carbene palladium(ii) generated from Pd(OAc) catalysts for carbonylative Suzuki coupling reactions of arylboronic acids with 2-bromopyridine under inert conditions leading to unsymmetrical arylpyridine ketones: synthesis, characterization and cytotoxic activities.

,-Substituted benzimidazole salts were successfully synthesized and characterized by H-NMR, C {H} NMR and IR techniques, which support the proposed structures. Catalysts generated were efficiently used for the carbonylative cross-coupling reaction of 2 bromopyridine with various boronic acids. The reaction was carried out in THF at 110 °C in the presence of KCO under inert conditions and yields unsymmetrical arylpyridine ketones.