Microwave-Assisted Synthesis of Symmetrical 1,4-Disubstituted Bis-1H-1,2,3-triazoles Using Copper N-Heterocyclic Carbene Catalysts

Bis-triazoles separated by a symmetrical linking group are joined at C4 of each triazole or at N1 of each triazole. Preparation of a series of bis-1H-1,2,3-triazoles derived from o-bis(azidomethyl)benzene and an alkyne is reported with use of copper N-heterocyclic carbene catalysis with microwave-assisted heating in an aqueous solvent. The products were symmetrical N1–N1′-bis-1H-1,2,3-triazoles. Additional syntheses utilized dialkynes and organic azides to prepare symmetrical C4–C4′-bis-1H-1,2,3-triazoles. Pure products were often obtained directly when water was used as the solvent with microwave-assisted heating. Results are given for experiments using conventional heating or no heating. Sonication results are given for a reaction where microwave-assisted heating was unsatisfactory.