Facile ionic liquid-mediated, multi component synthesis of dihydro-1H-furo[2,3-c]pyrazoles

A facile, convenient, efficient, and high-yielding diastereoselective synthesis of a novel fused dihydro-1H-furo[2,3-c]pyrazole by a one-pot four-component reaction of β-keto ester, hydrazine, aromatic aldehyde and pyridinium salt in the presence of [bmIm]OH ionic liquid medium provided with excellent yields. Three new bonds (two C‒C and one C‒O), and two stereo centres are generated in a single operation. Low cost, short reaction time, excellent yield, operational simplicity, and more importantly the purification of the compounds by a non-chromatographic method make this process very significant for academic research and practical applications.