6-CARBOXY-FLAVONE DERIVATIVES AND PROCESS FOR THEIR PREPARATION

摘要

This invention relates to compounds which have the following formula (I) (I) wherein R, is a) carboxy or b) -COOR4, wherein R4 is C1-C12 alkyl or C3-C4 alkenyl; R2 is a') C1-C6 alkyl, which m?? be unsubstituted or substituted by C1-C2 alkoxy, or b') C3-C4 alkenyl; R3 ?? C1-C4 alkyl, and the pharmaceutically acceptable salts with bases. It also relates to a process for the preparation of these compounds by the cyclization of a compound of formula (II) (II) and where this step may be followed by the conversion of a compound of general formula (I) into a pharmaceutically acceptable salt or, the conversion of a salt into a free compound of formula I. The compounds of this invention possess anti-allergic activity, which renders them useful in the prevention and treatment of bronchial asthma, allergic rhinitis, hay fever, urticaria and dermatosis.