1-{2-[(Tetrahydro-2H-pyran-2-yl)oxy]ethyl}-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole synthesis

Yield: 80%

Reaction Conditions:

Stage #1:4-iodo-1-[2-(tetrahydro-2H-pyran-2-yloxy)ethyl]-1H-pyrazole with isopropylmagnesium chloride in tetrahydrofuran at 0; for 1 h;
Stage #2:2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in tetrahydrofuran at 20; for 1 h;
Stage #3: with water;ammonium chloride in tetrahydrofuran

Steps:

42.2
Step 2 To a solution of 4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole (1.0 g, 3.1 mmol) in anhydrous THF (8 mL) was added iPrMgCl (2M in THF, 3.10 mL, 6.21 mmol) at 0° C. drop by drop under nitrogen. The reaction was stirred for 1 hour at 0° C. under nitrogen. To the solution was added 2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.736 g, 4.66 mmoL) at 0° C. and the resulting yellow solution was allowed to stir for 1 hour at ambient temperature under nitrogen. The reaction was quenched with sat. aqueous solution of NH₄Cl (10 mL). EtOAc (50 mL) and sat aqueous NH₄Cl solution (10 mL) were added. The organic layer was separated, and the aqueous layer was extracted with EtOAc (3*50 mL), dried over Na₂SO₄, and concentrated to give the crude product as yellow oil. The oil was purified a silica gel column eluding with EtOAc and hexanes to provide 1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole as clear oil (800 mgs, 80% yield). ¹H NMR (300 MHz, DMSO-d₆) δ 7.91 (s, 1H) 4.48-4.54 (m, 1H) 4.26-4.33 (m, 2H) 3.86-3.90 (m, 1H) 3.66-3.76 (m, 1H) 3.45-3.57 (m, 1H) 3.33-3.39 (m, 1H) 1.33-1.70 (m, 6H) 1.24 (s, 12H). on a high vacuum for 1 hour. The solid was re-crystallized from EtOH (50 mL) to provide 2-[4-(3-Quinolin-6-ylmethyl-3H-[1,2,3]triazolo[4,5-b]pyrazin-5-yl)-pyrazol-1-yl]-ethanol (400, 63% yield) as a white crystalline solid with a melting point of 222° C. ¹H NMR (400 MHz, DMSO-d6) δ 9.22 (s, 1H) 8.89 (dd, J=4.14, 1.70 Hz, 1H) 8.63 (s, 1H) 8.37 (dd, J=8.38, 1.04 Hz, 1H) 8.32 (s, 1H) 7.98-8.04 (m, 2H) 7.82 (dd, J=8.67, 2.07 Hz, 1H) 7.53 (dd, J=8.29, 4.14 Hz, 1H) 6.15 (s, 2H) 4.96 (t, J=5.27 Hz, 1H) 4.24 (t, J=5.46 Hz, 2H) 3.78 (q, J=5.46 Hz, 2H).

References:

PFIZER INC. US2007/265272, 2007, A1 Location in patent:Page/Page column 37; 39