Acetic Anhydride → Saikosaponin B2

Beteiligte Stoffe

Reaktionsschritte

By way of example, the fully acetylated saikosaponin d can be obtained by adding 10 to 20 ml of acetic anhydride to a solution of saikosaponin d in 10 to 20 ml/g of pyridine and allowing the mixture to stand at 10° C. to 50° C. for 3 to 16 hours. When this reaction mixture is stirred with a 1 to 40% (w/w) aqueous solution of ferric chloride at 10° C. to 40° C. for 1 to 10 hours for cleavage of the ether ring, there is obtained the acetylated saikosaponin b2 in which only the hydroxy group in the 28 position is free. This product is subjected to the above-described phosphorylation reaction with DPC and, then, to hydrolysis of the acetyl groups under alkaline conditions (pH 9-14, preferably pH 10-13), whereby the salt of saikosaponin b2 -28-(dihydrogen phosphate) is obtained. In the same manner as above, a salt of saikosaponin b1 -28-(dihydrogen phosphate) can be obtained from saikosaponin a, and a salt of saikosaponin h-28-(dihydrogen phosphate) from saikosaponin c.

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