| 摘要 |
This invention provides compounds of formula <IMAGE> wherein R1 is hydrogen, alkyl, alkenyl or alkynyl, the multiple bond of which is not adjacent to the nitrogen atom, R2 is, for example, hydrogen, alkyl, alkoxy, hydroxy or halogen, and R3 is hydrogen, halogen, hydroxyl, alkyl or alkoxy, useful, for example, in the treatment of allergic asthma. |
