Synthetic method of pyrone compounds
A synthesis method and compound technology, applied in the field of synthesis of pyrone compounds, can solve the problems of high cost, difficulty in scale-up, complex process route purification, etc., and achieve the effect of low cost, high conversion rate and low equipment requirements
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Embodiment 1
[0030] Synthesis of dimethyl 4-oxo-3-methoxy-4H-pyran-2,5-dicarboxylate
[0031]
[0032] Synthesis steps: Add 105ml of 1M lithium hexamethyldisilazide tetrahydrofuran solution into a three-necked flask, cool to -15°C under nitrogen protection, add 14.6g of methyl 4-methoxyacetoacetate dropwise while keeping warm, and then continue to drop 6.0g Methyl formate, after dropping, keep warm for 2h. Add 120ml of 1M lithium hexamethyldisilazide solution in tetrahydrofuran, then add 13.4g of dimethyl oxalate, raise the temperature to 20-25°C for 3h. The reaction solution was transferred to pre-cooled 300ml 2N hydrochloric acid, stirred at room temperature for 2 hours, concentrated to remove tetrahydrofuran, added ethyl acetate for extraction, the organic phase was washed with water, concentrated, and finally crystallized with isopropanol to obtain 4-oxo-3-methoxy- 16.5 g of dimethyl 4H-pyran-2,5-dicarboxylate, yield 68%.
Embodiment 2
[0034] Synthesis of Dimethyl 4-oxo-3-benzyloxy-4H-pyran-2,5-dicarboxylate
[0035]
[0036] Synthesis steps: Add 105ml of 1M tetrahydrofuran solution of lithium hexamethyldisilazide to a three-necked flask, cool to -15°C under nitrogen protection, add 22.2g of methyl 4-benzyloxyacetoacetate dropwise while keeping warm, and then continue to add 6.0 g methyl formate, after dropping, keep warm for 3h. Add 125ml of 1M tetrahydrofuran solution of lithium hexamethyldisilazide, and then add 13.6g of dimethyl oxalate, raise the temperature to 35-40°C for 3h. The reaction solution was transferred to pre-cooled 300ml 2N hydrochloric acid, stirred at room temperature for 2 hours, concentrated to remove tetrahydrofuran, added ethyl acetate for extraction, the organic phase was washed with water, concentrated, and finally crystallized with isopropanol to obtain 4-oxo-3-benzyloxy- 19.7 g of dimethyl 4H-pyran-2,5-dicarboxylate, yield 62%.
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