Synthesis and biological evaluation of novel pyrazolo[1,5-a]pyrimidines: Discovery of a selective inhibitor of JAK1 JH2 pseudokinase and VPS34.

A series of novel 3,6-di-substituted or 3-substituted pyrazolo[1,5-a]pyrimidines were prepared via a microwave-assisted approach that generated a broad array of derivatives in good yields (20-93%, ave. = 59%). The straightforward synthesis involved sequential treatment of commercially-available acetonitrile derivatives with DMF-dimethylacetal (120 °C, 20 min), followed by treatment with NHNH·HBr (120 °C, 20 min), and 1,1,3,3-tetramethoxypropane or 2-aryl-substituted malondialdehdyes (120 °C, 20 min).