合成路线1

N-Protection of 4-chloropyrrolo[2,3-d]pyrimidine (I) by means of SEM-Cl in the presence of NaH in DMAc or DMF yields the protected deazapurine (XX) , which is then subjected to Suzuki coupling with pinacol 1-(1-ethoxyethyl)-4-pyrazolylboronate (III) in the presence of K2CO3 and Pd(PPh3)4 in BuOH to give the pyrazol-deazapurine derivative (XXI). Without isolation, compound (XXI) is N-deprotected by acidic hydrolysis to afford the SEM-protected deazapurine (VIII) . Alternatively, intermediate (VIII) can be obtained by Suzuki coupling of N-SEM-4-chloropyrrolo[2,3-d]pyrimidine (XX) with unprotected pyrazolylboronate (XXII) in the presence of K2CO3 and Pd(PPh3)4 in DMF at 125 °C . Coupling of SEM-protected deazapurine (VIII) with N-Boc-3-(cyanomethylene)azetidine (XVII) in the presence of DBU in acetonitrile affords the corresponding acetonitrile derivative (XXIII) , which is then N-deprotected by means of HCl in CH2Cl2 or 1,4-dioxane to provide the azetidine derivative (XXIV) . Finally, condensation of compound (XXIV) with ethanesulfonyl chloride (XIX) using DIEA in THF/EtOAc, followed by N-deprotection of the resulting adduct (IX) with TFA in CH2Cl2 affords baricitinib trifluoroacetate .
Alternatively, N,N-deprotection of intermediate (XXIII) with TFA in CH2Cl2, followed by condensation of the resulting imine (XXVI) with ethanesulfonyl chloride (XIX) using Et3N in THF also results in baricitinib trifluoroacetate .