An efficient synthesis of novel spiro[indole-3,8′-pyrano[2,3-d][1,3,4]thiadiazolo[3,2-a]pyrimidine derivatives via 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 of novel derivatives of 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 of 7-hydroxy-2-phenyl-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one derivatives, malononitrile and isatin compounds in the presence of DABCO as a organocatalyst and under solvent-free conditions. In this report, a new family of spiro-pyrano-thiadiazolo-pyrimidine derivatives have been synthesized in short reaction times (10-60 min) and good to excellent yields (80-96%). The structures of all synthesized products have been confirmed by IR, H-1 NMR, C-13 NMR and mass spectrometry, and the structure of one selected product was characterized by single-crystal X-ray diffraction studies as well.

Automated summary

In this research, novel derivatives of 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 were synthesized via a one-pot three-component condensation reaction. The synthesized products were characterized by various spectroscopic techniques, with one product having its structure confirmed by single-crystal X-ray diffraction.