1-(ethoxyethyl)-4-bromo-1H-pyrazole

In the synthetic route, the ethoxyethyl group functions as a protecting group on the pyrazole nitrogen, allowing selective functionalization at the 4-bromo position. The bromine atom serves as a reactive site for cross-coupling reactions (such as Suzuki or similar palladium-catalyzed couplings), enabling the attachment of the substituted pyrrolo[2,3-d]pyrimidine core that is essential to the final molecule. After the key carbon–carbon bond formation, the protecting group is removed and further modifications are performed to yield the final Active Pharmaceutical Ingredient. 1-(Ethoxyethyl)-4-bromo-1H-pyrazole is an important synthetic intermediate used in the preparation of Ruxolitinib.