| 摘要 |
This invention is concerned with a novel process for the preparation of a compound of structural formula I <IMAGE> I wherein R1 and R2 independently are aryl, C2-15 alkenyl or C1-15 alkyl, either unsubstituted or substituted with one or three substituents, which can be the same or different, selected from the group consisting of Ra, wherein Ra belongs to a group consisting of C1-6 alkyl, aryl, halo, -N(R3)2, -NO2, -CN, -OR3, -C3-6 cycloalkoxy, -CO(R3), -COOR3, SO2R3 and -SR3; wherein R3 is selected from the group consisting of hydrogen, C1-6 alkyl, C2-6 alkenyl and aryl, said alkyl, alkenyl or aryl optionally substituted with 1 to 3 groups of Ra, which is an important antiasthmatic agent.
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