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5-Bromo-1-methyl-3-nitropyridin-2-one (41); A 1-L round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 5-bromo-3-nitro-2-hydroxypyridine (24.0 g, 0.11 mol), anhydrous DMF (280 mL) and powdered potassium carbonate (-350 mesh, 33.4 g, 0.24 mol), and the suspension stirred for 15 min at ambient temperature. After this time methyl iodide (17.1 g, 0.124 mol) was added, and the mixture stirred at room temperature for 18 h. The reaction mixture was then diluted with water (750 mL) and extracted with ethyl acetate (3×1.0 L). The organic extracts were combined, washed with brine (500 mL) and dried over sodium sulfate. After removing the drying agent by filtration, the filtrate was evaporated to dryness under reduced pressure. The resulting residue was purified by flash chromatography on silica to afford an 85% yield (21.7 g) of 41 as a yellow solid: mp 122-123 C.; 1H NMR (300 MHz, CDCl3) δ 8.37 (d, 1H, J=2.7 Hz), 7.26 (s, 1H), 3.68 (s, 3H); MS (ESI+) m/z 234 (M+H).
75%
With potassium carbonate; In N,N-dimethyl-formamide; at 20℃;
Intermediate 1 (7.0 g, 32 mmol),potassium carbonate (8.8 g, 64 mmol) and methyl iodide (5.5 g, 38.4 mmol) weresequentially added to N,N-dimethylformamide (70 mL) in,React overnight at room temperature.After the reaction was monitored by TLC, the reactionsolution was poured into ice water and extracted with ethyl acetate.The organic phase was washed with saturated brine, driedwith anhydrous sodium sulfate, filtered,The filtrate was separated by a concentration column(petroleum ether/ethyl acetate (v:v)=3/1) to obtain Intermediate 2(5.6 g, yield: 75%), the product is a yellow solid.
With caesium carbonate; In N,N-dimethyl-formamide; for 18h;
Cesium carbonate (44.6 g, 137 mmol) was added to a solution of 5-bromo-2-hydroxy-3- nitropyridine (20.0 g, 91.3 mmol) and iodomethane (19.4 g, 137 mmol) in NN-dimethylformamide (500 mL). After 18 h, the reaction mixture was quenched with water. The mixture was extracted with ethyl acetate (3x), and the combined organic extracts were washed with water, saturated brine, dried over sodium sulfate, filtered and concentrated. MS 233.1 (M).
5-Bromo-1-methyl-3-nitro-1H-pyridin-2-one H A 1-L round-bottomed flask equipped with a magnetic stirrer is purged with nitrogen, then charged with 5-bromo-3-nitro-pyridin-2-ol G (20.0 g; 0.09 mol), DMF (200 mL) and K2CO3 (25.2 g; 0.18 mol). The suspension is stirred for 15 min at RT, MeI (14.3 g; 0.10 mol) is added and the mixture is stirred at RT for 18 h. The reaction mixture is diluted with water and extracted with EtOAc (3*200.0 mL). The combined extracts are washed with brine, dried with Na2SO4, filtered, and concentrated under reduced pressure. The residue is purified by silica gel chromatography. HPLC-MS: (M+H)+=233/235; tRet=0.828 min; method M7
Example 1225-Bromo- l-methyl-3-nitropyridin-2(lH)-one 122a122aA 1-L round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 5-Bromo-3-nitropyridin-2(lH)-one (25.0 g, 114 mmol), anhydrous DMF (500 mL) and potassium carbonate (34.7 g, 251 mmol), and the suspension stirred for 15 min at ambient temperature. After this time, methyl iodide (17.8 g, 126 mmol) was added, and the mixture stirred at room temperature for 16 h. The reaction mixture was then diluted with water (500 mL) and extracted with methylene chloride (3 x 500 mL). The organic extracts were combined, washed with 10% aqueous lithium chloride (300 mL) and water (300 mL) and dried over sodium sulfate. After removing the drying agent by filtration, the filtrate was evaporated to dryness under reduced pressure. The resulting residue was flash chromatographed eluting with a gradient from 50% to 100% of ethyl acetate in hexanes, and the fractions containing 122a were collected to afford, after concentrating under reduced pressure, an 89% yield (23.6 g) of 122a as a yellow solid: mp 122-123 C; ]H NMR (300 MHz, CDC13) δ 8.37 (d, 1H, J = 2.7 Hz), 7.26 (s, 1H), 3.68 (s, 3H); MS (ESI+) m/z 234 (M+H).
With silver carbonate; In chloroform; at 20℃; for 48h;Inert atmosphere;
Silver carbonate (4.09 g, 14.84 mmol, 1.3 equivalents) and methyl iodide (7.11 mL, 114 mmol, 10 equivalents) were added to a covered flask containing 5-bromo-3-nitropyridin-2-one (2.5 g, 11.42 mmol, 1 equivalent) and CHCl3 (40 mL) and the reaction allowed to stir at ambient temperature for 2 days. The solution was then filtered through a pad of celite (5 g) and concentrated, giving a yellow solid which was purified by column chromatography (20% EtOAc in hexane, followed by DCM:EtOAc 1:1) to give 1.11 g (42%) of 1-methyl-3-nitro-5-bromopyridin-2-one as an orange solid.
[0447] Synthesis of compound 61.2. To a solution of 61.1 (5.0 g, 22.83 mmol, 1.0 equiv) in DMF (50 mL) was added potassium carbonate (6.6 g, 47.94 mmol, 2.1 equiv) and stirred for 15 min. To the mixture was added methyl iodide (3.56 g, 25.11 mmol, 1.1 equiv). The reaction mixture was stirred at room temperature for 1 h. It was poured over ice-water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to obtain 61.2. MS (ES): m/z 234.02 [M+H]+.
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