Hydrochloric Acid → (E)-Methyl 3-cyclopentyl-3-(4-(7-((2-(trimethylsilyl)ethoxy)methyl)-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl)acrylate

Participants

Reaction Steps

To a stirred suspension of 4-(1H-pyrazol-4-yl)-7-{[2-(trimethylsilyl)ethoxy]methyl}-7H-pyrrolo[2,3-d]pyrimidin (17, 12.08 g, 38.31 mmol) and methyl 3-cyclopentylprop-2-ynoate (18, 8.970 g, 45.97 mmol, 1.2 equiv) in acetonitrile (76 mL, 1400 mmol) at room temperature was added 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 2.92 mL, 19.2 mmol, 0.5 equiv). The resulting reaction mixture was stirred at room temperature for 2 h. When LCMS showed the reaction was deemed complete, the reaction mixture was quenched with water (50 mL) and 1 N aqueous HCl solution (20 mL). The quenched reaction mixture was adjusted to pH 4 after treatment with 1 N aqueous HCl solution. The mixture was then extracted with EtOAc (2×100 mL) and the combined organic layers were washed with brine, dried over magnesium sulfate (MgSO4), filtered and concentrated under reduced pressure. The residue was purified by Combiflash (SiO2, 0-50% EtOAc/hexane gradient elution) to afford (E)-methyl 3-cyclopentyl-3-(4-(7-((2-(trimethylsilyl)ethoxy)methyl)-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl)acrylate (21, 6.838 g, 17.92 g theoretical, 38% in yield) as a colorless, very viscous oil. For 19: 1H NMR (CDCl3, 400 MHz) δ ppm 8.93 (s, 1H), 8.55 (bs, 1H), 8.44 (s, 1H), 7.49 (d, 1H, J=3.5 Hz), 6.86 (d, 1H, J=3.5 Hz), 6.34 (s, 1H), 5.74 (s, 2H), 4.56 (m, 1H), 3.84 (s, 3H), 3.60 (t, 2H, J=8.2 Hz), 2.01 (m, 2H), 1.96 (m, 4H), 1.77 (m, 2H), 0.98 (t, 2H, J=8.2 Hz), 0.00 (s, 9H); C24H33N5O3Si (MW, 467.64), LCMS (EI) m/e 468.2 (M++H).

Provenance & Evidence