| 摘要 |
A 3(2H)pyridazinone of the formula: (I) wherein R1 is hydrogen or C1-C5 alkyl; R2 is hydrogen, C1-C8 alkyl, chlorine or bromine; A is -NR3- or -O-; X is (CH2)n-, -CH(OR4)-, -CO- or a single bond; when X is -(CH2)n- or a single bond, B is O-, -S-, -NH-, -OSO2-, or -OCO- or a single bond, when X is -CH(OR4)-, B is -O-, -S-, -NH- or OSO2-, and when X is -CO-, B is -O- or -S-; and each of Y1, Y2 and Y3 which may be the same or different, is hydrogen, C1-C8 alkyl, C2-C8 alkenyl, halogen, -OR5, -CO2R6, CH=CHCO2R7, , -CON(R8)(R9), -COR10, or two of Y1, Y2 and Y3 together form , and a pharmaceutically acceptable salt thereof. Compounds of the formula (I) as defined above are useful for reducing the incidence or severity of an allergy induced in a subject by SRS-A. |
