Development of a Practical Synthesis of a Pyrazolopyridinone-Based p38 MAP Kinase Inhibitor

A practical synthesis of the pyrazolopyridinone-based p38 MAP kinase inhibitor (4) was required for an ongoing program. The synthesis of a key pyrazolopyridinone building block was refined and optimized to provide kilogram quantities of 10 without chromatography or extractive workups. An efficient building-block strategy was employed to give optimal control of the key quality attributes, and in situ Raman spectroscopy was used to monitor and understand the complex solid-state properties of 4.