| 摘要 |
This invention provides new compounds of formula I, <IMAGE> I wherein the indicated radical in the 8 or 9 position of the benzonaphthyridine structure (R1) is hydrogen, alkoxy of 1 to 4 carbon atoms or hydroxy, and R2, R3 and R4 are selected in certain combinations from hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, benzyloxy, hydroxy, halogen, nitro, amino, dimethylamino, or -NHCOR5 wherein R5 is hydrogen or alkyl of 1 to 4 carbon atoms, USEFUL AS BRONCHOSPASMOLYTICS.
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