To methyl 2-[(dimethylamino)methyl]prop-2-enoate (314 mg, 2.19 mmol) in tetrahydrofuran (1.4 mL) and water (1.4 mL) was added LiOH (52.5 mg, 2.19 mmol). The solution was stirred at 40° C. for 4 hours, before being frozen and lyophilized to afford sodium 2-[(dimethylamino)methyl]prop-2-enoate which was used as is in the next step as is. To a solution of ethyl 4-(3-aminophenyl)-7H-pyrrolo[2,3-d]pyrimidine-5-carboxylate (100 mg, 0.354 mmol) in DMF (886 μL) was added sequentially sodium 2-[(dimethylamino)methyl]prop-2-enoate (96 mg, 0.71 mmol), 4 M solution of HCl in dioxane (177 μL, 0.708 mmol), TEA (197 μL, 1.42 mmol), and 1-propanephosphonic acid cyclic anhydride (422 μL, 0.708 mmol) at room temperature. The reaction was stirred overnight before being purified by reverse phase HPLC using an acetonitrile gradient in water with 0.1% TFA modifier. The combined fractions with the desired product were concentrated until only the water layer remained and the water layer was neutralized with saturated aqueous sodium bicarbonate and the mixture was extracted with ethyl acetate (×5). The combined organic fractions were dried with sodium sulfate, filtered and concentrated under reduced pressure to give ethyl 4-[3-({2-[(dimethylamino)methyl]acryloyl}amino)phenyl]-7H-pyrrolo[2,3-d]pyrimidine-5-carboxylate. LRMS (ESI) calc'd for C21H24N5O3 [M+H]+: 394, found 394. 1H NMR (600 MHz, DMSO-D6) δ 12.9 (s, 1H), 11.1 (s, 1H), 8.90 (s, 1H), 8.30 (s, 1H), 7.89 (s, 1H), 7.77 (d, 1H, J=8.21 Hz), 7.42 (t, 1H, J=8.21 Hz), 7.35 (d, 1H, J=7.63 Hz), 6.01 (s, 1H), 5.58 (s, 1H), 3.87 (q, 2H, J=7.04 Hz), 3.23 (s, 2H), 2.24 (s, 6H), 0.86 (t, 3H, J=7.04 Hz).
