An efficient synthesis of novel spiro[indole-3,8′-pyrano[2,3-<i>d</i>][1,3,4]thiadiazolo[3,2-<i>a</i>]pyrimidine derivatives <i>via</i> organobase-catalyzed three-component reaction of malononitrile, isatin and heterocyclic-1,3-diones

In this research, firstly, some derivatives of sulfur containing [1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one have been synthesized and then they were used for the synthesis novel 6′-amino-2,9′-dioxo-2′-phenyl-9′H-spiro[indoline-3,8′-pyrano[2,3-d][1,3,4]thiadiazolo[3,2-a]pyrimidine]-7′-carbonitriles via a one-pot three-component condensation reaction 7-hydroxy-2-phenyl-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one derivatives, malononitrile isatin compounds in presence DABCO as organocatalyst under solvent-free conditions. report, new family spiro-pyrano-thiadiazolo-pyrimidine short times (10–60 min) good to excellent yields (80–96%). The structures all products confirmed by IR, 1H NMR, 13C NMR mass spectrometry, structure one selected product was characterized single-crystal X-ray diffraction studies well.