Sophisticated synthesis of monosubstituted piperazines – from a batch reaction vessel to a flow (microwave) reactor

We report a novel sophisticated synthetic method for preparation of monosubstituted piperazine derivatives, which can now be easily prepared in a one-pot-one-step way from a free piperazine with no need of introduction of a protecting group bringing further disadvantages in terms of time, costs and reduced yields. Reactions proceeding either at room or higher temperatures in common solvents employ with advantage heterogeneous catalysis by metal ions supported on commercial polymeric resins.

Further, we have picked up a set of piperazine derivatives and studied the possibilities of microwave acceleration of given synthetic reactions. Our investigation proceeded from a simple batch technique to the construction of a flow microwave reactor and resulted in promising findings which are summarized and discussed in our contribution.