Reaction Steps
2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-(tert-butyl-dimethyl-silanyloxy)-indole-1-carboxylic acid tert- butyl ester [Intermediate (63), LC-MS: 570 (M+H), RT=4.2 minutes; 1H NMR [(CD3)2SO]: δ 7.98 (1H,d), 7.56 (2H,dd), 7.35(1H, d), 7.06 (1H, s), 6.86 (1H, dd), 1.65 (s, 9H), 1.33 (s, 3H), 0.99 (s, 9H), 0.23 (s, 6H)] was prepared in 46% yield using procedures similar to those of Example 5C, substituting 6-(tert-butyl-dimethylsilyloxy)-1H-indole-2-boronic acid [Intermediate (74), prepared by the application of method described in Example 4-6 of International Patent Application Publication No. WO 02/32861] for 5-(tert-butyl-dimethylsilanoxy)-1H-indole-2-boronic acid. Step 2. To a solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-(tert-butyl-dimethyl-silanyloxy)-indole-1-carboxylic acid tert-butyl ester [0.87 g, 1.51 mmol, Intermediate (63)] in chloroform (15 mL) was added bromine (95 μL, 1.81 mmol). The reaction was stirred at room temperature overnight. A sodium bisulfite solution was added until the orange mixture turned to pale yellow. The mixture was extracted with diethyl ether. The organic layer was dried over magnesium sulfate and concentrated. The residue was chromatographed through silica gel (n-heptane/ethyl acetate, 95/5 then 80/20 as eluant) to provide 0.49 g of a monodeprotected product, 3-[3-bromo-6-(tert-butyl-dimethyl-silanyloxy)-1H-indol-2-yl]-thieno[3,2-c]pyrazole-1-carboxylic acid tert-butyl ester or 3-bromo-6-(tert-butyl-dimethyl-silanyloxy)-2-(1H-thieno[3,2-c]pyrazol-3-yl)-indole-1-carboxylic acid tert-butyl ester as a powder. This material was dissolved in dichloromethane (5 mL). Then di-tertbutyl dicarbonate (0.28 g, 1.10 mmol), triethylamine (0.15 mL, 0.98 mmol) and DMAP (0.03 g, 0.18 mmol) were added. The mixture was stirred at room temperature for 30 minutes. The solvent was removed. The residue was chromatographed through silica gel (n-heptane-ethyl acetate, 96:4 as eluant) to produce 3-bromo-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-(tert-butyl-dimethyl-silanyloxy)-indole-1-carboxylic acid tert-butyl ester [0.33 g, 33%, Intermediate (64)] as a white powder. LC/MS: 648.1 (M+H), RT=3.82 minutes. Step 3. To a solution of 3-bromo-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-(tert-butyl-dimethyl-silanyloxy)-indole-1-carboxylic acid tert-butyl ester [0.32 g, 49 mmol, Intermediate (64)] in tetrahydrofuran at 0° C. was added a 1.0 M TBAF solution in tetrahydrofuran (0.51 mL, 0.51 mmol). The resulting solution was stirred at 0° C. for 30 minutes. The solvent was removed. The residue was chromatographed through silica gel (dichloromethane/ethyl acetate, 95/05 as eluant) to produce 3-bromo-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-hydroxy-indole-1-carboxylic acid tert-butyl ester [0.22g, 83%, Intermediate (65)] as an orange foam. Step 4. To 3-bromo-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-hydroxy-indole-1-carboxylic acid tert-butyl ester [0.22 g, 0.40 mmol, Intermediate (65)] in 1,3 dibromopropane (4 mL) was added cesium carbonate (0.33 g, 1.0 mmol). The resulting suspension was stirred at 75° C. for 1 hour then filtered. The insoluble was filtered off. The filtrate was concentrated. The residue was chromatographed through silica gel (n-heptane/ethyl acetate, 100/0 then 90/10) to provide 3-bromo-6-(3-bromo-propoxy)-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-indole-1-carboxylic acid tert-butyl ester [0.19 g, 72%, Intermediate (66)] as a white foam. LC/MS: 654.0 (M+H), RT=4.71 minutes. Step 5. To 3-bromo-6-(3-bromo-propoxy)-2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-indole-1-carboxylic acid tert-butyl ester [0.17 g, 0.26 mmol, Intermediate (66)] in acetonitrile (4 mL) were added polymer supported DIEA (0.14 mg, 0.52 mmol) and 4-hydroxypiperidine (53 mg, 0.52 mmol). The mixture was gently stirred at 70° C. for 4 hours. It was then filtered and concentrated. The residue was dissolved in dichloromethane (2 mL) and anisole (0.5 mL). Trifluoroacetic acid (0.5 mL) was added. The resulting bright yellow solution was stirred at 40° C. overnight as it turned to a greenish solution. It was directly loaded onto a cationic ion exchange column (SCX mega bond elut from VARIAN, 5 g), washed with methanol and eluted with 1.0 M ammonia in methanol. The appropriate fractions were combined and concentrated. The residue was chromatographed twice through silica gel (dichloromethane/1.0M ammonia in methanol, 85/15 as eluant) to provide 3-bromo-6-(3-piperidin-1-yl-propoxy)-2-(1H-thieno[3,2-c]pyrazol-3-yl)-1H-indole [29 mg, 23%, Example 61] as a purple powder. LC/MS: 475.08 (M+H), RT=2.55 minutes; 1H NMR [300 Mhz, (CD3)2SO]: δ 13.45 (s, 1H), 11.59 (s, 1H), 7.69 (d, J=5.2 Hz, 1H), 7.27 (d, J=8.3 Hz, 1H), 7.15 (d, J=5.2 Hz, 1H), 6.91 (s, 1H), 6.75 (d, J=8.0 Hz, 1H), 4.60 (brs, 1H), 3.99 (m, 2 H), 3.47 (m, 1H), 2.80 (m, 2H), 2.11 (m, 2H), 1.92 (m, 2H), 1.73 (m, 2H), 1.42 (m, 2H), 1.13 (m, 2H).
