EP0075607B1 — 1-azaxanthone for use as therapeutic agent, processes for its production and pharmaceutical compositions

USPTO Abstract

The invention concerns 1-azaxanthone for use as a therapeutic agent, especially as antipyretic/analgesic, antiinflammatory or diuretic agent, bronchodilator and antibronchoconstrictor agent in human or animal therapy or as spasmolytic agent in human and animal therapy in processes of spastic ethiology or in which spasticity is a symptom. <??>The invention also concerns a pharmaceutical composition comprising 1-azaxanthone in association with non-toxic, pharmaceutically acceptable excipients, carriers or adjuvants. <??>The new process for the production of 1-azaxanthone of high purity is characterized in that 2-phenoxynicotinic acid is slowly added to 5-10 times its weight of previously heated 80-85 % (as P2O5) polyphosphoric acid, the reaction mixture is diluted with water and partly neutralized with concentrated alkalihydroxide to a pH value of 2-3. The reaction temperature is 160-200 DEG C. <??>Furthermore the 1-azaxanthone can be produced by reaction of a compound of formula <CHEM> wherein X is Cl, Br or C1-4 alkoxy, and R is halogen, (preferably F) OH or C1-4 alkoxy, with concentrated hydrochlorid or hydrobromic acid under reflux.