Simple and clean access to pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine derivatives using solvent-
free and HSBM techniques through the multi-component reaction of 3-methyl-1-phenyl-1Hpyrazol-
5-amine, 1-aryl-2-thiocyanatoethan-1-one and aromatic aldehydes are reported. Using
2-hydroxyethan-1-aminium acetate as an ionic liquid, the product in high yields is obtained.