Reaktionsschritte
300 mg of ethyl 1-(2′,4′-dichlorophenyl)-1,4,5,6-tetrahydro-thieno[3′,2′:6,7]cyclohepta[1,2-c]pyrazol-3-carboxylate prepared in example 9e are solubilized in THF/H2O 4:1 (7 mL). Lithium hydroxide (72 mg; 2.7 mmoles) is added and the mixture is heated to 60° C. for 5 hours. After cooling at room temperature, it is diluted first by adding water (5 mL) and then a HCl 1N solution to lower the pH to 1-2. A precipitate is formed which is recovered by filtration and then washed with ethyl ether (2×10 mL). 200 mg of 1-(2′,4′-dichlorophenyl)-1,4,5,6-tetrahydro-thieno[3′,2′:6,7]cyclohepta[1,2-c]pyrazol-3-carboxylic acid are obtained (white solid; yield 72%). Rf=0.76 (chloroform/methanol 9/1 volume/volume); 1H NMR (CDCl3) δ (ppm): 7.58 (d, 1H, ArH), 7.45 (m, 2H, ArH), 7.04 (d, 1H, ArH), 6.80 (d, 1H, ArH), 3.30 (m, 2H, CH2), 3.00 (m, 2H, CH2), 2.07 (m, 2H, CH2); 13C NMR (CDCl3) δ (ppm): 163.4, 143.6, 141.3, 139.3, 137.5, 136.0, 135.0, 131.6, 130.5, 130.2, 128.2, 125.1, 123.8, 122.4, 31.0, 25.9, 24.1; FT-IR (film) νmax: 3078.0, 2929.3, 2854.1, 2715.1, 1683.4, 1450.3, 1386.6, 1251.4, 1204.2, 705.8, 665.3 cm−1.
