Novel and Efficient Synthesis of 7-Trifluoromethyl-Substituted Pyrazolo[1,5-a] Pyrimidines with Potent Antitumor Agents

The synthesis of 7-trifluoromethyl-substituted pyrazolo(1,5-a) pyrimidines with potent antitumor agents was investigated. The trifluoromethyl-β- diketones were treated with 5-amino pyrazole carboxylates under microwave condition, using acetic acid as a solvent to provide the pyrazolo(1,5-a) pyrimidine carboxylates. Cell viability was determined by 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Melting points were measured with Koeffler melting point apparatus and are uncorrected. Thin-layer chromatography (TLC) was performed on aluminum sheets precoated with silica gel. Elution started with water and ended with acetonitrile/water and used a linear gradient at a flow rate of 0.15 mL/min and an analysis cycle time of 25 min. All solvents and reagents were obtained from commercial sources and were used without purification.