Reaction of ketone alkylhydrazones with phosphorus trichloride: a general mild route to substituted pyrroles
Abstract
A new convenient and mild procedure for the synthesis of symmetrically and unsymmetrically substituted pyrroles is described. This one-pot synthesis consists of two different stages. The first stage, addition of PCl3 to an alkylhydrazone, is always carried out at room temperature. The second stage, addition of an enolizable ketone to the previous reaction mixture, is performed at room temperature, or at 80 °C under reduced pressure. The results provide clear evidence that diazaphosphole derivatives being formed in the first stage are intermediates in this pyrrole synthesis.