反应详情

Part A. A 1-L flame-dried flask was charged with 130 mL of LiHMDS (130 mmol; 1.0 M in THF) and 410 mL of ethyl ether. The resulting solution was cooled to −78° C. and 2-acetylfuran (14 g, 12 m mmol) was added in one portion. After 5 min, di-tert-butyl oxalate was added dropwise over 1 h as a solution in 100 mL of ether. The resulting mixture was warmed to 23° C. over a period of 3 h and was maintained at rt for 20 h. The mixture was then filtered, and the resulting beige precipitate was washed with 100 mL of ether. The filter cake was then dried in a vacuum oven for 1 h to afford lithium 1-tert-butoxy-4-(2-furyl)-1,4-dioxo-2-buten-2-olate (25 g, 83%) as a cream colored solid. 1H NMR (DMSO-d6) δ 7.75 (t, 1H), 6.96 (m, 1H), 6.56 (m, 1H), 3.34 (s, 2H), 1.46 (s, 9H). Part B. To the product (13 g, 54 mmol) from Part A was added 2-fluoro-5-hydrazinobenzonitrile hydrochloride (10 g, 54 mmol) and 250 mL of acetic acid. The resulting orange mixture was maintained at rt for 20 h and then concentrated to dryness. The resulting residue was taken up in 30% CHCl3 in hexanes and filtered to afford tert-butyl 1-(3-cyano-4-fluorophenyl)-5-(2-furyl)-1H-pyrazole-3-carboxylate (18 g, 95%) as a light brown solid. LC/MS (ESI+): 354.2 (M+H)+. 1H NMR (CDCl3) δ 7.64–7.78 (m, 3H), 7.42 (s, 1H), 7.05 (s, 1H), 6.45 (S, 1H), 6.30 (s, 1H), 1.61 (s, 9H). Part C. To the product from Part B (10 g, 28 mmol) was added 125 mL of CH2Cl2 and 125 mL of trifluoroacetic acid. The resulting black solution was maintained at rt under N2 for 2 h and was then concentrated to dryness. The resulting solid was dried in a vacuum oven for 4 h to afford 1-(3-cyano-4-fluorophenyl)-5-(2-furyl)-1H-pyrazole-3-carboxylate (8.4 g, 99%) as a brown solid. LC/MS (ESI+): 298.1 (M+H)+. 1H NMR (CD3OD) δ 7.90 (m, 1H), 7.75 (m, 1H), 7.51 (s, 1H), 7.46 (t, 1H), 6.98 (s, 1H), 6.47 (m, 1H), 6.35 (m, 1H). Part D. To the product (4.1 g, 14 mmol) from Part C was added 23 mL of CH2Cl2 and 2.0 M oxalyl chloride (10 mL, 21 mmol) in CH2Cl2. Upon dropwise addition of DMF (10 drops) to the brown mixture, all solids dissolved over a period of 30 min. When no more gas evolved, the brown solution was concentrated. The resulting residue was redissolved in 100 mL of CH2Cl2 and 0.5 M ammonia in dioxane (110 mL, 55 mmol) was added via cannula. After 30 min, the resulting suspension was concentrated and poured into H2O. The aqueous layer was washed with ethyl acetate (3×70 mL), and the combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated. The resulting residue was dissolved in 10 mL of CH2Cl2 and 50 mL of hexanes were added. The resulting suspension was filtered, and the filter cake was washed with 50 mL of hexanes. The filter cake was dried in a vacuum oven to afford 1-(3-cyano-4-fluorophenyl)-5-(2-furyl)-1H-pyrazole-3-carboxamide (2.5 g, 62%) as a brown solid. LC/MS (ESI+): 297.1 (M+H)+. 1H NMR (CDCl3) δ 7.75 (m, 1H), 7.64 (m, 1H), 7.42 (s, 1H), 7.33 (t, 1H), 7.16 (s, 1H), 6.79 (br s, 1H), 6.46 (m, 1H), 6.36 (m, 1H), 5.50 (br s, 1H). Part E. To the product (2.5 g, 8.3 mmol) from Part D was added H2O (51 mL), 5% aqueous NaH2PO4 (35 mL), and tert-butanol (51 mL). The resulting mixture was warmed to 60° C., and KMnO4 (8.0 g, 51 mmol) was added over a period of 10 min. After an additional 10 min, the resulting purple slurry was cooled to 0° C., and the reaction was quenched by the addition of 200 mL of saturated aqueous sodium bisulfite. The resulting mixture was filtered, washed with 300 mL of H2O, and the filtrate was acidified with conc. HCl. The aqueous layer was extracted with EtOAc (6×100 mL) and the combined organic layers were washed with brine, dried over Na2SO4, and filtered. Concentration afforded 3(aminocarbonyl)-1-(3-cyano-4-fluorophenyl)-1H-pyrazole-5-carboxylic acid (1.6 g, 71%) as a yellow solid. LC/MS (ESI+): 275.1 (M+H)+. 1H NMR (CD3OD) δ 8.03 (m, 1H), 7.90 (m, 1H), 7.5 (t, 1H), 7.44 (s, 1H). Part F. 5-Nitro-1H-indole (2.5 g, 15 mmol), di-tert-butyl dicarbonate (3.6 g, 17 mmol), and DMAP (190 mg, 1.5 mmol) were dissolved in 150 mL of THF. The solution was stirred for 12 h at rt under N2 and was then concentrated. The residue was taken up in EtOAc and the mixture was filtered. The filtered solid was washed with 100 mL of hexanes and dried to give tert-butyl-5-nitro-1H-indole-1-carboxylate as an off-white solid (3.1 g, 78%). LRMS (AP+): 304.2 (M+H+ACN)+. 1H NMR (CDCl3) δ 8.51 (d, 1H), 8.23–8.29 (m, 2H), 7.75 (d, 1H), 6.73 (d, 1H), 1.71 (s, 9H). Part G. The product from Part F (1.0 g, 4.3 mmol) was dissolved in 100 mL of MeOH. Palladium hydroxide, 20 wt % Pd, Degussa type (100 mg), was added, and the resulting mixture was subjected to a hydrogen atmosphere (50 psi) and shaken vigorously. After 5 h, the black mixture was filtered and concentrated to afford tert-butyl-5-amino-1-indolinecarboxylate as a brown oil (0.98 g, 98%). LRMS (ESI+): 235.2 (M+H)+. 1H NMR (CDCl3) δ 6.88 (br m, 3H), 3.96 (m, 2H), 3.04 (m, 2H), 1.55 (br s, 9H). Part H. To tert-butyl-5-amino-1-indolinecarboxylate (1.90 g, 8.2 mmol) was added 5-bromovaleryl chloride (1.4 mL, 9.0 mmol) and 18 mL of THF. After stirring for 5 min at rt under N2, potassium tert-butoxide (9 mL, 9 mmol; 1.0 M in THF) was added in one portion, and the resulting brown solution was stirred under N2 for 30 min. A second portion of potassium tert-butoxide (9 mL) was added, and the resulting brown suspension was stirred for 15 min. An additional 0.10 mL-portion of 5-bromovaleryl chloride and a 4.5 mL-portion of potassium tert-butoxide were added, and the mixture was stirred for 30 min. The reaction was then poured into H2O (80 mL). The aqueous layer was washed with EtOAc (3×50 mL), and the combined organic layers were washed with brine, dried over Na2SO4, and filtered. The filtrate was concentrated and the resulting residue was purified by radial chromatography (50% EtOAc in hexanes) to afford tert-butyl 5-(2-oxo-1-piperidinyl)-1-indolinecarboxylate as a pink solid (1.30 g, 50%). LRMS (AP+): 317.2 (M+H)+. 1H NMR (CDCl3) δ 7.40–7.80 (br m, 1H), 7.01 (s, 1H), 6.97 (d, 1H), 3.94 (t, 2H), 3.55 (br m, 2H), 3.09 (t, 2H), 2.49 (br m, 2H), 1.91 (br m, 4H), 1.52 (s, 9H). Part I. The product from Part H (1.30 g, 4.2 mmol) was dissolved in 30 mL of CH2Cl2 and stirred at rt under N2. Trifluoroacetic acid (30 mL) was added, and the reaction was stirred for 2 h. The yellow solution was concentrated, and the resulting residue was dissolved in EtOAc (50 mL) and washed with saturated aqueous NaHCO3. The aqueous layer was washed with EtOAc (2×50 mL) and the combined organic layers were dried over Na2SO4 and concentrated to afford 1-(2,3-dihydro-1H-indol-5-yl)-2-piperidinone (740 mg, 81%) as a beige solid (LC/MS (ESI+): 217.2 (M+H)+). To this solid was added 3-(aminocarbonyl)-1-(3-cyano-4-fluorophenyl)-1H-pyrazole-5-carboxylic acid (1.00 g, 3.8 mmol)(see Part E above), followed by 28 mL of pyridine and 6.8 mL of DMF. 1,3-Diisopropyl-carbodiimide (0.59 mL, 3.8 mmol) was added, and the resulting solution was stirred for 14 h. The reaction was then poured into 1N aqueous HCl (70 mL) and washed with EtOAc (3×50 mL). The combined organic layers were washed with brine, dried over Na2SO4, and filtered. Concentration of the filtrate afforded crude 1-(3-cyano-4-fluorophenyl)-5-{[5-(2-oxo-1-piperidinyl)-2,3-dihydro-1H-indol-1-yl]carbonyl}-1H-pyrazole-3-carboxamide (1.20 g; LC/MS (ESI+): 473.2 (M+H)+) as a brown residue. This residue was dissolved in 18 mL of DMF and 3 mL of H2O. Potassium carbonate (1.70 g, 13 mmol) and acetohydroxamic acid (470 mg, 6.2 mmol) were added, and the resulting mixture was warmed to 50° C. under an N2 atmosphere. After 2 h, the reaction was cooled to rt and poured into EtOAc (60 mL). The organic layer was washed with H2O (2×50 mL), brine, and dried over Na2SO4. Filtration and concentration afforded a brown oily residue that was purified by preparative LC/MS (C18 reverse phase, eluted with 0.05% TFA in CH3CN/H2O) to give the TFA salt of the final product. This salt was dissolved saturated aqueous NaHCO3 (15 mL), and the aqueous layer was washed with EtOAc (3×50 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated to give 1-(3-amino-1,2-benzisoxazol-5-yl)-5-{[5-(2-oxo-1-piperidinyl)-2,3-dihydro-1H-indol-1-yl]carbonyl}-1H-pyrazole-3-carboxamide as a white solid (150 mg, 7.3% for 2 steps). LC/MS (ESI+): 486.2 (M+H)+. 1H NMR (DMSO-d6) δ 8.08 (s, 1H), 7.91 (d, 1H), 7.85 (s, 1H), 7.67 (m, 1H), 7.51–7.57 (br m, 2H), 7.37 (s, 1H), 7.2 (s, 1H), 7.04 (s, 1H), 6.58 (s, 2H), 4.28 (br m, 2H), 3.55 (br s, 2H), 3.15 (br m, 2H), 2.36 (br s, 2H), 1,82 (br s, 4H).

1. stirringthe resulting brown solution was stirred under N2 for 30 min
2. stirringthe resulting brown suspension was stirred for 15 min
3. stirringthe mixture was stirred for 30 min
4. washThe aqueous layer was washed with EtOAc (3×50 mL)
5. washthe combined organic layers were washed with brine
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationThe filtrate was concentrated
9. customthe resulting residue was purified by radial chromatography (50% EtOAc in hexanes)