Piperazine: An excellent catalyst for the synthesis of 2-amino-3-cyano-4H-pyrans derivatives in aqueous medium.

An improved, forthright, and highly efficient one-pot synthesis of a wide range of pharmaceutically exciting diverse kind of functionalized 2-amino-3-cyano-4H-pyrans and especially bis-pyrans compounds is developed using piperazine as a low-cost and environmentally benign commercially available basic catalyst in aqueous media. The attractive features of this process are simple procedure, short reaction times, high yields, no column chromatographic separation and commercial availability and recyclability of the catalyst. Also, piperazine can catalyze the synthesis of the target compounds on a larger scale. Furthermore, rational mechanism was suggested via GC-Mass analysis of the trapped intermediates.