tin pyrophosphate (snp2o7): as a novel heterogeneous and highly efficient catalyst for the one pot-three component synthesis of tetrahydrobenzo[b]pyran and dihydropyran[c]chromene derivatives

The tin pyrophosphate (snp2o7) was synthesized from the modification of mono-ammonium phosphate (map) by tin chloride (sncl2). this solid was used as a heterogeneous catalyst for the one-pot multicomponent synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[3,2-c]chromenes derivatives under green reaction conditions. this synthetic protocol offers several advantages such as short reaction times (8-15 min), high product yields (85-97%), easy work‐up procedure, and easy catalyst separation from the reaction mixture. in addition, snp2o7 can be recycled for up to five cycles without a significant loss of catalytic reactivity. the xrd and ir spectra confirm the stability and heterogeneity of snp2o7 in the reaction medium even after its reuse.