CA1265798A — 3(2h)pyridazinone, process for its preparation and anti-allergic agent containing it

USPTO Abstract

ABSTRACT A 3(2H)pyridazinone of the formula: wherein R1 is C2-C5 alkyl; R2 is hydrogen, C1-C3 alkyl, chlorine or bromine; R3 is hydrogen or C1-C4 alkyl; and each of Y1, Y2 and Y3 which may be the same or different, is hydrogen, C1-C8 alkyl, C2-C8 alkenyl, halogen, -(CH2)?A [wherein A is substituted amino of the formula -N(R4)(R5) (wherein each of R4 and R5 which may be the same or different, is C1-C4 alkyl, or R4 and R5 together form C4-C6 alkylene), morpholino, 4-R6-piperazin-1-yl (wherein R6 is C1-C3 alkyl) or -OR7 (wherein R7 is hydrogen or C1-C3 alkyl), and ? is an integer of n to 3], -OR8 [wherein R8 is hydrogen, C1-C8 alkyl, C3-C5 alkenyl, benzyl or -(CH2)q-R9 [wherein R9 is CO2R3 (wherein R3 is as defined above), -CONHR3 (wherein R3 is as defined above) or -CH2OR7 (wherein R7 is as defined above), and q is an integer of 1 to 5]], -CO2R3 (wherein R3 is as defined above), -CON(R10)(R11) [wherein each of R10 and R11 which may be the same or different, is hydrogen, C1-C4 alkyl or C3-C5 alkenyl, or R10 and R11 together form C4-C6 alkylene, _(CH2)2O(CH2)2- or -(CH2)2N(R6)(CH2)2- (wherein R6 is as defined above)] -CONH (CH2)mA (wherein A is as defined above, and m is an integer of 2 to 4), -CH=CHCOR12 (wherein R12 is hydroxy, C1-C4 alkoxy or -N(R13)(CH2)nCO2H3 (wherein R13 is hydrogen, C1-C6 alkyl or cycloalkyl, R3 is as defined above, and n is an integer of 1 to 4)), -SR14 (wherein R14 is C1-C4 alkyl), -CN or (wherein R3 is as defined above), or two of Y1, Y2 and Y3 together form (wherein p is an integer of 1 or 2), and a pharma-ceutically acceptable salt thereof. The compound exhibits anta-gonism against slow reacting substance of anaphylaxis (SRS-A) which induces a contraction of bronchial smooth muscle, and thus is useful as an anti-allergic agent.