Method for preparing compound
A technology of compound and magnesium chloride, applied in the field of compound shown in the preparation formula I, can solve problems such as inconvenience for industrialized production, difficult separation of intermediates, harsh reaction conditions, etc., achieve environmental protection, reduction of impurity types and quantities, and production steps. short effect
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Embodiment 1
[0063] Preparation of 2,3,4,6-tetra-O-acetyl-β-D-gluconolactone (compound shown in formula 3):
[0064]
[0065] Add acetic anhydride (1710g, 16.75mol) and 192g trifluoroacetic acid (192g, 1.68mol) to a 3L reaction flask, add 300g gluconolactone (300g, 1.68mol) under stirring at room temperature, and keep the temperature at 20-30°C for the reaction. After 14 hours of reaction, the gluconolactone solid disappeared, and then the mixture was concentrated under vacuum to remove acetic anhydride, and then the syrupy product was dissolved with 1L of toluene, and washed with 3 times the volume of saturated sodium bicarbonate water under ice bath conditions until neutral. After washing once with saturated NaCl water, the organic phase was concentrated to dryness to obtain 583 g of the compound shown in Formula 3 (purity: 97.8%), and the molar yield: 100%.
Embodiment 2
[0067] The preparation of compound shown in formula I:
[0068] Stir the compound shown in formula 1 (300g, 0.81mol) in 300ml tetrahydrofuran at room temperature. ), the dropwise addition was completed in about 30 minutes, and the resulting solution was stirred at -20 to 10°C for about 1 hour, then cooled and the temperature of the system was controlled at -30 to -20°C.
[0069] Dissolve the compound (336 g, 0.97 mol) represented by formula 3 in Example 1 with an equal weight of tetrahydrofuran, add it dropwise to the previous reaction system, and drop it in about 1 hour. After stirring for 30 minutes at -30 to -20°C, Add 500ml of 6% hydrochloric acid aqueous solution, raise the temperature to 20°C, and dilute with water. The system was allowed to stand for liquid separation, and the organic layer was separated. The organic layer was concentrated under reduced pressure, and the obtained oil was dissolved in 1.8 L of acetonitrile and used directly in the next step.
[0070] C...
Embodiment 3
[0072] The preparation of compound shown in formula I:
[0073] The compound shown in formula 1 (300g, 0.81mol) was stirred in 300ml tetrahydrofuran at room temperature, cooled to -15~-5°C under a nitrogen atmosphere, and isopropylmagnesium chloride.Lithium chloride (1062ml, 1.38mol ), the dropwise addition was completed in about 30 minutes, and the resulting solution was stirred at -15 to -5°C for 1 hour, then cooled and the temperature of the system was controlled at -40 to -30°C.
[0074] Dissolve the compound shown in Formula 3 (561g, 1.62mol) with tetrahydrofuran of equal weight, and add it dropwise to the previous reaction system. The dropwise addition is completed in about 1 hour. After stirring for 30 minutes at -40~-30°C, add 500ml of 6% hydrochloric acid Aqueous solution, heated to 20 ° C, diluted with water. The system was allowed to stand for liquid separation, and the organic layer was separated. The organic layer was concentrated under reduced pressure, and the ...
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