合成路线1

N-Protection of 4-chloropyrrolo[2,3-d]pyrimidine (I) with either 2-(trimethylsilyl) ethoxymethyl chloride (SEM-Cl) in DMA or pivaloyloxymethyl chloride (POM-Cl) in THF in the presence of NaH yields the protected deazapurines (IIa) and (IIb) , respectively, which by Suzuki coupling with pinacol 1-(1-ethoxyethyl)-4-pyrazolylboronate (III) by means of Pd(PPh3)4 and K2CO3, followed by acidic hydrolysis of the ethoxyethyl group, affords the respective pyrazolyl deazapurines (Va) and (Vb) . Alternatively, intermediate (Va) can be obtained by Suzuki coupling of deazapurine (IIa) with unprotected pyrazolylboronate (IV) by means of Pd(PPh3)4 and K2CO3 in DMF/H2O at 125 °C . Michael addition of pyrazole derivative (Va) to 3-cyclopentylacrylonitrile (VI) (obtained by Wittig condensation of cyclopentylcarboxaldehyde [VII] with diethyl cyanomethylphosphonate [VIII] by means of t-BuOK in THF) in the presence of DBU in acetonitrile, followed by resolution using chiral preparative HPLC, provides the desired (R)-adduct (IXa) . Alternatively, in an enantioselective procedure, asymmetric aza-Michael reaction of (Va) or (Vb) with (E)-3-cyclopentylacrylaldehyde (X) in the presence of p-nitrobenzoic acid (p-NBA) and a chiral diarylprolinol silyl ether in CHCl3 gives aldehydes (XIa) and (XIb), which by subsequent condensation with NH4OH, followed by oxidation of the intermediate imines with I2 in aqueous solution, leads to the corresponding nitriles (IXa) and (IXb) . Finally, ruxolitinib is obtained by deprotection of compound (IXa) by sequential treatment with LiBF4 in refluxing acetonitrile/H2O followed by aqueous NH4OH , or with TFA in CH2Cl2 and subsequent basification of obtained TFA salt with ethylenediamine (EDA) in MeOH , or by deprotection of compound (IXb) by treatment with NaOH in MeOH/H2O .
In an alternative strategy, ruxolitinib can be directly obtained by Suzuki coupling of unprotected 4-chloropyrrolo[2,3-d]pyrimidine (I) with the pyrazolylboronate (XII) in the presence of Pd(PPh3)4 and K2CO3 in 1,4-dioxane/H2O at 100 °C .