Condensation of propargylic alcohols with N-methylcarbazole and carbazole in [bmim]PF6 ionic liquid; synthesis of novel dipropargylic carbazoles using TfOH or Bi(NO3)3·5H2O as catalyst

A series of doubly-propargylated N-methylcarbazole and carbazole derivatives were synthesized in good to excellent isolated yields in (bmim)PF6 using triflic acid (10 mol %). The use of bismuth nitrate (20 mol %) instead of triflic acid allowed stepwise propargylation employing two different propargylic alcohols, to prepare mixed bis-propargylated carbazoles. Simple product isolation, mild reaction conditions, and repeated recycling and reuse of (bmim)PF6 are added advantages of this IL-mediated synthetic method.