Abstract
Herein, click reaction is used for the preparation of novel organic-inorganic Bronsted acidic ionic solids (BAISs) as new catalysts for the efficient synthesis of tetrazolopyrimidines. A series of mono and disubstituted-1,2,3-triazoles were synthesized under click reaction condition. The prepared 1,2,3-triazoles underwent reaction with 1,4-butanesultone to provide novel solid 1,2,3-triazolium N- butyl sulfonate zwitterions. Then, the reaction of phosphotungstic acid with the obtained zwitterions led to the novel 1,2,3-triazolium-N-butyl sulfonic acid phosphotungstate as acidic ionic solids. The synthesized BAIS catalysts were fully characterized using FTIR, H-1 and C-13 NMR, XRD, elemental analysis (CHNS), TG and DSC techniques. The introduced novel hybrids were used as efficient catalysts for the synthesis of targeted methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate and 6,6-dimethyl-9-aryl-5,6,7,9-tetrahydrotetrazolo[5,1-b]quinazolin-8(4H)-one derivatives via multicomponent reaction of aromatic aldehydes, active methylene compounds and 5-aminotetrazole. Low amount of the prepared 1,2,3-triazolium-N-butyl sulfonic acids phosphotungstate catalysts (5-10 mmol%) gave desired products in short times (20-45 min) with excellent yields (87-93%). Novelty of the introduced catalysts, ease of recovery and reusability up to four repeated runs with no significant decrease in the yields are highlighted superiorities of the introduced organic-inorganic hybrid catalysts.