Preparation method for cannflavin compounds

A preparation method for a cannflavin compound, comprising the following steps:

• step (1):
• condensing 4′-hydroxy-3′-methoxyacetophenone and diethyl carbonate under an alkaline condition to obtain ethyl 4′-hydroxy-3′-methoxybenzoylacetate;
• step (2):
• reacting 1,3,5-trihydroxybenzene with bromo-isoamylene under an alkaline condition to obtain 2-isopentenyl-1,3,5-trihydroxybenzene;
• and
• step (3):
• reacting ethyl 4′-hydroxy-3′-methoxybenzoylacetate with 2-isopentenyl-1,3,5-trihydroxybenzene to obtain cannflavin B and/or isocannflavin B;
• wherein the step (2) comprises the following steps:
• adding water and potassium hydroxide into a reaction vessel, stirring, then adding 1,3,5-trihydroxybenzene, cooling, adding dropwise bromo-isoamylene, stirring, reacting, and then performing post-treatment on the resulting reaction liquid to obtain 2-isopentenyl-1,3,5-trihydroxybenzene;
• for the step (2):
• a molar ratio of 1,3,5-trihydroxybenzene to bromo-isoamylene is 1:1 to 2:1;
• the reaction temperature is 0-15° C.;
• the post-treatment comprises a quenching step, and the quenching step comprises:
• adding ethyl acetate to the reaction vessel, and adding an acid to adjust pH of the mixture to 4.0-7.0;
• the post-treatment further comprises an extraction step after the quenching step, and the extraction step comprises:
• adding ethyl acetate to the reaction liquid, and layering;
• adding ethyl acetate to the aqueous layer for extraction, and layering;
• combining the organic layers, washing, layering, and then combining the organic layers.