Example 16
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1) Synthesis of Compound 17-1
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Propionyl chloride (12.91 g, 139.50 mmol) was added to a solution of Compound 11-1 (10.00 g, 46.50 mmol) in trichloromethane (200 mL) at 20° C. The reaction mixture was heated to 70° C., and reacted for 12 h. The reaction mixture was cooled to room temperature, and concentrated to obtain a crude product. Ethyl acetate (100 mL) was added to the crude product and the resulting mixture was stirred at 25° C. for 0.5 h, and filtered. The collected filter cake was dried in a drying oven to obtain Compound 17-1. LCMS (ESI) m/z: 253 (M+1).
2) Synthesis of Compound 17-2
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2-Bromoethanol (1.24 g, 9.88 mmol, 0.7 mL) was added to a mixed solution of Compound 17-1 (1.00 g, 3.95 mmol), potassium carbonate (1.36 g, 9.88 mmol), benzyltriethylammonium chloride (90 mg, 395.00 μmol), and dimethoxyethane (20 mL). The resulting reaction mixture was heated to 90° C., and stirred for 16 h. 2-Bromoethanol (1.24 g, 9.88 mmol, 0.7 mL) and benzyltriethylammonium chloride (135 mg, 592.70 μmol) were supplemented to the reaction mixture. The resulting reaction mixture was heated to 90° C., and stirred for 16 h. The reaction mixture was filtered, and the filtrate was concentrated under reduced pressure. The residue obtained from the concentration was purified by a silica gel column to obtain Compound 17-2. 1H NMR (400 MHz, CDCl3) δ ppm 8.30 (d, J=2.0 Hz, 1H), 7.87 (dd, J=2.3, 8.8 Hz, 1H), 7.75 (d, J=8.8 Hz, 1H), 4.80-4.72 (m, 2H), 4.08 (br d, J=3.5 Hz, 2H), 3.31 (br s, 1H), 2.96 (q, J=7.5 Hz, 2H), 1.40 (t, J=7.7 Hz, 3H).
3) Synthesis of Compound 17-3
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diBoc (171 mg, 783.51 μmol), triethylamine (139 mg, 1.37 mmol, 0.19 mL), and 4-dimethylaminopyridine (10 mg, 81.85 μmol) were added to a mixed solution of Compound 17-2 (200 mg, 673.06 μmol) in dichloromethane (4 mL). The resulting reaction mixture was stirred at 10° C. for 1 h. The reaction mixture was concentrated under reduced pressure. The residue obtained from the concentration was purified by a silica gel column to obtain Compound 17-3. LCMS (ESI) m/z: 397 (M+1).
4) Synthesis of Compound 17-4
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A mixture of Compound 17-3 (130 mg, 327.24 μmol), Boc-NH2 (50 mg, 426.80 μmol), cesium carbonate (266 mg, 816.40 μmol), bis(dibenzylideneacetone)palladium (20 mg, 34.78 μmol), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (20 mg, 34.56 μmol), and methylbenzene (2 mL) was added to a microwave tube, and kept at 120° C. for microwave reaction for 0.5 h. The reaction mixture was filtered through Celite. The filtrate was diluted with ethyl acetate (30 mL), washed with water (20 mL) and saturated brine (20 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue obtained from the concentration was purified by a preparative TLC plate to obtain Compound 17-4. LCMS (ESI) m/z: 434 (M+1).
5) Synthesis of Compound 17-5
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Trifluoroacetic acid (0.2 mL) was added to a solution of Compound 17-4 (85 mg, 196.08 μmol) in dichloromethane (2 mL). The resulting reaction mixture was stirred at 15° C. for 12 h. A saturated aqueous solution of sodium bicarbonate was added to the reaction mixture (pH about 8), which was extracted with dichloromethane (20 mL). The organic phase was washed with saturated brine (20 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Lithium hydroxide (82 mg, 1.95 mmol) was added to a solution of the resulting yellow oil (64 mg, 194.37 μmol) in tetrahydrofuran (2 mL) and water (0.5 mL). The resulting reaction mixture was stirred at 15° C. for 16 h. The reaction mixture was dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain Compound 17-5. LCMS (ESI) m/z: 234 (M+1).
6) Synthesis of Compound 17-6
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Trimethylsilyl cyanide (25 mg, 252.00 μmol) and zinc chloride (4 mg, 29.32 μmol) were added to a mixed solution of Compound 17-5 (20 mg, 85.74 μmol), cyclobutanone (36 mg, 513.63 μmol), sodium sulfate (50 mg, 352.01 μmol) and tetrahydrofuran (2 mL). The resulting reaction mixture was stirred at 10° C. for 19 h. An aqueous solution of sodium sulfite (5 mL) was added to the reaction mixture, which was extracted with ethyl acetate (5 mL×3). The organic phase was washed with saturated brine (10 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain Compound 17-6. LCMS (ESI) m/z: 313 (M+1).
7) Synthesis of Compound 17-7
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diBoc (23 mg, 105.39 μmol), triethylamine (20 mg, 197.65 μmol), and 4-dimethylaminopyridine (2 mg, 16.37 μmol) were added to a mixed solution of Compound 17-6 (30 mg, 96.04 μmol) in dichloromethane (1 mL). The resulting reaction mixture was stirred at 10° C. for 1 h. The reaction mixture was concentrated under reduced pressure. The residue obtained from the concentration was purified by a preparative TLC plate to obtain Compound 17-7. LCMS (ESI) m/z: 413 (M+1).
8) Synthesis of Compound 17-8
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A mixed solution of Compound 17-7 (20 mg, 48.49 μmol), Compound 1-7 (28 mg, 122.70 μmol), methylbenzene (1 mL), and DMF (0.2 mL) was heated to 110° C., and stirred for 16 h. Compound 1-7 (54 mg, 236.64 μmol) was supplemented to the reaction mixture, and the resulting mixture was further stirred at 110° C. for 4 h. Methanol (1 mL) was added to the reaction mixture, which was stirred for 30 min, and then concentrated under reduced pressure. The residue obtained from the concentration was purified by a preparative TLC plate (petroleum ether/ethyl acetate=1/1) to obtain Compound 17-8. LCMS (ESI) m/z: 642 (M+1).
9) Synthesis of Compound 17
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Trifluoroacetic acid (0.2 mL) was added to a solution of Compound 17-8 (30 mg, 46.75 μmol) in dichloromethane (1 mL). The resulting reaction mixture was stirred at 10° C. for 2 h. A saturated aqueous solution of sodium bicarbonate was added to the reaction mixture (pH about 8), which was extracted with dichloromethane (10 mL×3). The organic phase was washed with saturated brine (15 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue obtained from the concentration was purified by a preparative TLC plate to obtain Compound 17. 1H NMR (400 MHz, CDCl3) δ ppm 8.09 (d, J=2.3 Hz, 1H), 8.01 (d, J=8.8 Hz, 1H), 7.92 (dd, J=3.1, 5.1 Hz, 2H), 7.80 (dd, J=1.8, 8.3 Hz, 1H), 7.64 (dd, J=2.5, 8.8 Hz, 1H), 4.77-4.69 (m, 2H), 4.07-3.98 (m, 2H), 3.12-2.81 (m, 3H), 2.73-2.62 (m, 2H), 2.59-2.46 (m, 2H), 2.26-2.13 (m, 1H), 1.65-1.55 (m, 1H), 1.38-1.33 (m, 3H); LCMS (ESI) m/z: 542 (M+1).