Thienopyrimidine Coupling Route for Higher-Yield Production

The patent combines multiple reaction steps into a single coupling reaction step. The synthesis route merges the formation of the thienopyrimidine core with the attachment of the piperidine-pyrazole moiety in one operation, using a palladium-catalyzed coupling reaction that directly connects the brominated thienopyrimidine with the amino-pyrazole compound, thereby reducing the number of steps and improving yield

The patent segments the synthesis into two main parts: preparation of the brominated thienopyrimidine intermediate and preparation of the amino-pyrazole intermediate, followed by a coupling step. This segmentation allows for optimized conditions in each step while maintaining overall efficiency, and the intermediates can be prepared independently and combined in the final coupling reaction

The patent extracts and removes the need for column chromatography by optimizing the reaction conditions and workup procedure. The coupling reaction is designed to proceed with high regioselectivity and stereoselectivity, producing the desired compound as the major product that can be isolated by simple filtration and washing, eliminating the need for complex chromatographic separation

The patent changes the reaction parameters including using palladium carbonate as catalyst, adding base (potassium carbonate or cesium carbonate), controlling temperature (80-100°C), and using specific solvents (acetonitrile or dimethylformamide) to achieve clean reaction profile that simplifies purification. These parameter optimizations enable the reaction to proceed with high selectivity, reducing the need for complex purification methods