Green Synthesis of Biologically Active Pyrazolopyrimidine Derivatives Using an Ionic liquid 2-Methyl-3-butylimidazolium chloride

Pyrazolopyrimidine derivatives have received a great deal of attention due to their pharmacological activities. Avoiding the use of organic solvents in synthesis is a paradigm shift directed at developing more benign chemistry, and with ionic liquids surprisingly can lead to access to new compounds. The application of ionic liquids in organic synthesis also provides chemical processes with special emphases such as enhanced reaction rates, absence of highly inflammable solvents, higher yields of pure products, better selectivity, reusability of the ionic liquid catalyst, rapid optimization of reactions in parallel and several eco-friendly advantages. An efficient and environmental benign method is reported for the synthesis of some Pyrazolopyrimidine derivatives using 3methyl-1-phenyl-5-pyrazolone with carbonyl compounds in ionic liquid 2-methyl-3-butyl imidazolium chloride. It is noteworthy to mention that this method of synthesis requires less time, less temperature, better yield and less amount of by-products than conventional reactions. The recyclability and reusability of the catalyst have been tested. The structures of all the synthesized Pyrazolopyrimidine derivatives have been established on the basis of elemental and spectral analysis. The compounds have been screened for their antimicrobial activity against various micro-organisms. All the compounds showed moderate to good activity against different micro-organisms at 256μg/ml.