| 摘要 |
There is described a process for the production of a compound of formula I, I in which R5, R6, R7 and R8 can be a variety of substituents, and E is a -COOH group or an N-(tetrazol-5-yl)carboxamide group, or a pharmaceutically acceptable derivative thereof, which comprises selective hydrolysis or oxidation of a compound of formula II or IV, II IV or an ester of either thereof, in each pair of Y and Z, Z is hydrogen and Y is hydrogen or hydroxy, or, when the reaction involves hydrolysis, in each pair c? Y and Z both Y and Z are halogen. The compounds produced by the novel process claimed are pharmaceutically useful, e.g. as anti-allergics. |
