PURPOSE: To easily and economically obtain the highly pure compound by acylating intermediate with 1,9-o-isopropylidene protected and then eliminating the protecting group.
CONSTITUTION: After introducing 1,9-o-isopropylidene protecting group into forskolin, the compound of formula I is obtained by common acylation and/or acyl-transfer method. The objective compound of formula II is obtained by treating at 0-80°C, preferably 25-60°C, for 72 hours, preferably 1-24 hours, in the solution of pH1.0-3.5, preferably pH1.0-1.3, and then eliminating 1,9-o- isopropylidene protecting group. In formula I, R1 and R2 are each OH, acetoxy or OCOC(R3)2(CH2)nX [R3 is H or alkyl; (n) is 0-10; X is H, halogen, alkyl, NR4R5 (when R4 and R5 are the same, these are each H or alkyl and when these are different, R4 is H and R5 is alkyl, aryl or aralkyl), etc.]; (a) is additional bonding.
PUREMANANDO DOURUGARAO DESAI
SHIYURIKANTO BISHIYUWANATO SAB
YURUGEN BURUUMUBAHA
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