Reaction Steps
To a solution of methyl 2-((4S,5S)-1-(4-(((3R,4R)-1-(5-ethoxy-2-fluorophenyl)-3-methylpiperidin-4-yl)oxy)phenyl)-4-methyl-3-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-5-yl)acetate (2.57 g, 4.66 mmol) in THF (85 mL) and water (8.5 mL) was added a 1 M aqueous solution of LiOH (58.2 mL, 23.3 mmol) and the reaction mixture was stirred at rt until complete for 1 h. The reaction mixture was concentrated to remove the THF and hexanes were added. An emulsion formed. The layers were separated as much as possible. Brine was added to the emulsion and the layers separated completely. The combined aqueous layer and brine aqueous layer was acidified to pH 2 with 1 M aqueous HCl. The product was extracted with CH2Cl2 (3×) and the combined organic layers were dried (MgSO4) and concentrated to provide 2-((4S,5S)-1-(4-(((3R,4R)-1-(5-ethoxy-2-fluorophenyl)-3-methylpiperidin-4-yl)oxy)phenyl)-4-methyl-3-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-5-yl)acetic acid (2.4720 g, 4.60 mmol, 99% yield) as a white foam. To a solution of 2-((4S,5S)-1-(4-(((3R,4R)-1-(5-ethoxy-2-fluorophenyl)-3-methylpiperidin-4-yl)oxy)phenyl)-4-methyl-3-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-5-yl)acetic acid (7.72 g, 14.4 mmol) in acetonitrile (50 mL) was added 3 N aqueous HCl (9.57 mL, 28.7 mmol). The solution was concentrated. 2-((4S,5S)-1-(4-(((3R,4R)-1-(5-ethoxy-2-fluorophenyl)-3-methylpiperidin-4-yl)oxy)phenyl)-4-methyl-3-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-5-yl)acetic acid, HCl (8.08 g, 14.0 mmol, 97% yield) was isolated as an off-white solid. LC-MS Anal. Calc'd for C27H31F4N3O4: 537.55. found [M+H] 538.3. 1H NMR (400 MHz, CD3CN) δ 7.99 (br. s., 1H), 7.24 (ddd, J=12.0, 9.3, 1.2 Hz, 1H), 7.12-7.04 (m, 2H), 7.02-6.93 (m, 3H), 4.47-4.38 (m, 1H), 4.18 (td, J=10.0, 4.1 Hz, 1H), 4.04 (q, J=6.9 Hz, 2H), 3.78-3.65 (m, 2H), 3.62 (dd, J=12.4, 4.1 Hz, 1H), 3.42 (td, J=11.8, 4.4 Hz, 1H), 3.37-3.27 (m, 1H), 2.83 (br. s., 1H), 2.73 (dd, J=16.5, 3.0 Hz, 1H), 2.54-2.38 (m, 2H), 2.36-2.28 (m, 1H), 1.37 (t, J=7.0 Hz, 3H), 1.30 (d, J=7.2 Hz, 3H), 1.11 (d, J=6.9 Hz, 3H). Analytical HPLC (Orthogonal method) RT=13.3 min, HI: 97%. hGPR40 EC50=154 nM. hGPR40 IP1 EC50=11 nM. Acute oral glucose tolerance: −52% @ 0.3 mg/kg (average of two experiments).
