| 主权项 |
1. A process for the purification of the compound of Formula IV: wherein or a protecting group for carbonyl group; P1 and P2 are independently protecting groups for hydroxyl groups; is a single or double bond; R2 is a single bond or a C1-4-alkylene or —CH2O—; and R3 is a C1-7-alkyl or an aryl or an aralkyl, each of which is unsubstituted or substituted by a C1-4-alkyl, a halogen or a trihalomethyl; and X is OH, OR6, or NR4R5 wherein R4 and R6 are independently C1-7-alkyl, and R5 is H or C1-7-alkyl, comprising the steps of: (1) macrolactonization of a compound of Formula IV-1 containing 0˜5% 5,6-trans isomer or other stereoisomers: wherein or a protecting group for carbonyl group and , P1, P2, R2 and R3 are as defined above, to form a compound of Formula III and unmacrolactonization isomers of the compound of Formula IV-1 or its derivative: wherein , P1, R2 and R3 are as defined above, (2) removing the unmacrolactonization isomers of the compound of Formula IV-1 or its derivative, and (3) opening the macrolactone ring of the compound of Formula III by hydrolysis, transesterification or amidation to form a compound of Formula IV. |
