Reaction Steps
A mixture of 5-(tert-butyl-dimethyl-silanyloxymethyl)-1H-indole-2-boronic acid 1-carboxylic acid tert-butyl ester [3.82 g, 9.42 mmol, Intermediate (8), prepared as described in Example 1-4 of International Patent Application Publication No. WO 02/32861], 3-iodo-thieno[3,2-c]pyrazole-1-carboxylic acid tert-butyl ester [4.0 g, 11.42 mmol, Example 5B above], tetrakis(triphenylphosphine)palladium(0) (544 mg, 0.470 mmol), potassium carbonate (2M aqueous, 12 mL) in tetrahydrofuran (60 mL) is purged with N2 for 10 minutes then heated to 55-60° C. for 7.5 hours. The reaction is diluted with ethyl acetate (50 mL) and washed with water (20 mL). Water layer is back extracted with ethyl acetate (50 mL). The combined ethyl acetate phases are dried over sodium sulfate. The residue is chromatographed on 35 g silica gel cartridge (5-30% ethyl acetate gradient in heptane) to give 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-(tert-butyl-dimethyl-silanyloxymethyl)-indole-1-carboxylic acid tert-butyl ester [3.8 g, 69%, Intermediate (9)]; 1H NMR [(CD3)2SO)]: δ 8.08 (2H, m), 7.64 (1H, s), 7.38 (2H, m), 7.14 (1H, s), 4.81 (2H, s, —OCH2), 1.65 (9H, s), 1.32 (9H, s) 0.92 (9H, s, Si(CH3)3), 0.10 (6H, s, Si(CH2)); LC/MS: 584 (M+H). Step 2. A solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-(tert-butyl-dimethyl-silanyloxymethyl)-indole-1-carboxylic acid tert-butyl ester [3.8 g, 6.51 mmol, Intermediate (9)]) in anhydrous tetrahydrofuran (40 mL) is cooled to 0° C. To it is added tetrabutylammonium fluoride (1M in tetrahydrofuran, 10 mL) drop wise. Stirred at 0° C. for 20 minutes then at room temperature for 20 minutes. Water (20 mL) is added and extracted three times with ethyl acetate (30 mL). The combined ethyl acetate phases are washed with brine and dried over sodium sulfate. The residue is chromatographed on 35 g silica gel (10-50% ethyl acetate in heptane) to give 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxymethyl-indole-1-carboxylic acid tert-butyl ester [2.63 g, 85%, Intermediate (10)] as white solid; 1H NMR [(CD3)2SO)]: δ 8.05 (2H, m), 7.62 (1H, s), 7.38 (2H, m), 7.02 (1H, s), 5.21 (1H, t), 4.6 (2H, d), 1.64 (9H, s), 1.25 (9H, s); LC/MS: 470 (M+H). Step 3. To a solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxymethyl-indole-1-carboxylic acid tert-butyl ester [200 mg, 0.426 mmol, Intermediate (10)] in tetrahydrofuran (5 mL) is added KOH (1M aqueous, 2.5 mL) and heated to 60° C. for 20 hours. The solvent is removed and dissolved crude in water. The water layer is neutralized with 3N hydrochloric acid then extracted twice with ethyl acetate (20 mL). The combined ethyl acetate phases are washed with brine and dried over sodium sulfate. Purification by chromatography using 10 g silica gel cartridge (50% ethyl acetate in heptane then ethyl acetate) afforded [2-(1H-thieno[3,2-c]pyrazol-3-yl)-1H-indol-5-yl]-methanol (84 mg, 74%, Example 23) as a light yellow solid; 1H NMR [(CD3)2SO)]: δ 13.22 (1H, s), 11.43 (1H, s), 7.77 (1H), 7.56 (1H), 7.38 (1H), 7.20 (1H), 7.04 (1H), 6.61 (1H), 5.02 (1H, OH), 4.57 (2H, —CH2OH); LC/MS: 270 (M+H).
