Entecavir intermediate and preparation method thereof
A technology for entecavir and intermediates, which is applied in the field of entecavir intermediates and their preparation, can solve the problems of being unsuitable for industrialized production, difficult to obtain, and low in product yield.
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Embodiment 1
[0155]
[0156] Example 1-1 is in compound 2 (R1 is ) (30.1g, 86.5mmol) in water (6500mL) were added potassium bicarbonate (260g, 2600mmol), potassium fluoride (100g, 1720mmol). 30% hydrogen peroxide (550 g, 4320 mmol) was slowly added to the obtained mixed solution at 70 degrees Celsius. After the dropwise addition, the mixed solution was incubated at 70 degrees Celsius and stirred for 3 hours, then added acetic acid (1150 mL), and continued to be incubated at 70 degrees Celsius and stirred for 30 minutes. The mixture was filtered through diatomaceous earth and then slowly cooled to 5°C. The powdered crystals collected by filtration were washed with distilled water at 5°C, redispersed in 2500mL of distilled water, and heated to 95°C to dissolve them completely. The resulting supernatant was slowly cooled to 5°C. The obtained powdery crystals were collected by filtration and dried to obtain 121.3 g of the desired target compound, with a yield of 89%.
[0157] 1 H NMR ...
Embodiment 2
[0164]
Embodiment 2-1
[0166] Compound 3-1 (R 2 for P 2 To a solution of benzyl) (82.0 g, 165 mmol) in dichloromethane (82 mL) was added concentrated sulfuric acid (8.2 mL, 98%). The resulting brown liquid was stirred at 25°C for 2 hours and then slowly dropped into an aqueous potassium hydroxide solution (2M, 1.6L). After the obtained mixed solution was evaporated to dryness of the organic solvent, acetic acid was added to adjust the pH=6-7. The solid obtained is collected by filtration and dried to obtain the desired target compound 2-1 (R 1 for ) 50g, yield 87%.
[0167] 1 H NMR (400MHz, CDCl 3 ): δ7.64(s, 1H), 5.30(s, 2H), 5.16-5.10(m, 1H), 3.88-3.72(m, 2H), 3.56-3.46(m, 1H), 2.52-2.38(m , 1H), 2.17-1.92(m, 2H), 1.90-1.75(m, 1H), 1.73-1.54(m, 4H), 1.00-0.70(m, 4H);
[0168] 13 C NMR (100MHz, CD 3 OD): δ159.4, 155.2, 153.9, 153.1, 129.1, 117.4, 112.1, 63.2, 59.7, 44.1, 30.1, 19.5, 17.1, 8.6,
[0169] ESI-MS: 348.1[M+H] + .
[0170] Example 2-2 to Example 2-8 were prepared accordin...
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