Synthetic method of entecavir intermediate
A synthesis method and compound technology, applied in the field of medicine, can solve the problems of serious environmental pollution, low yield, large dosage, etc., and achieve the effects of good atom economy, high product yield and less solid waste.
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Embodiment 1
[0029] Ti(OiPr) at room temperature 4 (0.2eq) Slowly add TiCl dropwise 4 (0.2eq) in dichloromethane solution (2V), add and stir at room temperature for 1h (standby); add Nysted (4.0eq) tetrahydrofuran solution into the reaction flask (nitrogen protection), cool to -75°C, Slowly add the above-mentioned Ti ligand mixed solution to the system dropwise, keep the temperature of the system not higher than -65°C, after the addition is completed, keep the reaction for 4 hours, and at the same time dissolve N6 (1.0eq) in tetrahydrofuran (2V), Slowly add it dropwise to the system, keep the system temperature at -65°C, after the addition is complete, return to room temperature under nitrogen protection until the end of the reaction, filter with diatomaceous earth, extract, combine the filtrates, concentrate to dryness under reduced pressure, and purify by column chromatography to obtain the target product N7 (HPLC: greater than 98.5%, yield: 67%).
[0030] 1HNMR (400MHz, CDCl 3 ):7.86...
Embodiment 2
[0033] Ti(OiPr) at room temperature 4 (0.2eq) Slowly add TiCl dropwise 4 (0.8eq) in dichloromethane solution (6V), add and stir at room temperature for 2h (standby); add Nysted (4.0eq) tetrahydrofuran solution into the reaction flask (nitrogen protection), cool to -70°C, Slowly add the above-mentioned Ti ligand mixed solution to the system dropwise, keep the system temperature at -60°C, after the addition is complete, keep it warm for 1 hour, and at the same time dissolve N6 (1.0eq) in tetrahydrofuran (4V), and slowly add it dropwise In the system, keep the temperature of the system at -60°C. After the addition is complete, return to room temperature under nitrogen protection until the end of the reaction, filter with diatomaceous earth, extract, combine the filtrates, concentrate to dryness under reduced pressure, and purify by column chromatography to obtain the target product N7 (HPLC: Greater than 98.5%, yield: 90%).
[0034] 1HNMR (400MHz, CDCl 3 ):7.86(s,1H),7.41-7.31...
Embodiment 3
[0037] Ti(OiPr) at room temperature 4 (0.2eq) Slowly add TiCl dropwise 4 (1.2eq) in dichloromethane solution (10V), add and stir at room temperature for 4h (standby); add Nysted (4.0eq) tetrahydrofuran solution into the reaction flask (nitrogen protection), cool to -70°C, Slowly add the above-mentioned Ti ligand mixed solution to the system dropwise, keep the system temperature at -70°C, after the addition is complete, keep it warm for 2 hours, and at the same time dissolve N6 (1.0eq) in tetrahydrofuran (8V), and slowly add it dropwise In the system, keep the temperature of the system at -70°C, after the addition is complete, return to room temperature under nitrogen protection until the reaction is complete, filter with diatomaceous earth, extract, combine the filtrates, concentrate under reduced pressure to dryness, and purify by column chromatography to obtain the target product N7 (HPLC: Greater than 98.5%, yield: 75%).
[0038] 1HNMR (400MHz, CDCl 3):7.86(s,1H),7.41-7....
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