PYRIDAZINONE DERIVATIVES OR THEIR SALTS, PROCESSES FOR THEIRPRODUCTION, AND ANTI-SHOCK AGENTS CONTAINING THEM

A pyridazinone derivative of formula (1) or a pharmaceutically acceptable salt thereof, wherein Q is -CH2- or -CO-, A is a furanyl group which may be substituted, a thienyl group which may be substituted, a pyridyl group which may be substituted, a pyridyl N-oxide group which may be substituted, a thiazolyl group which may be substituted, or a phenyl group which may be substituted, R1 is a hydrogen atom, an alkyl group which may be substituted, an alkenyl group which may be substituted, an alkynyl group which may be substituted, or a phenyl group which may be substituted, R2 is a hydrogen atom, a cyano group, an alkyl group which may be substituted, a hydroxyl group, an alkoxy group, a dioxanyl group which may be substituted by an alkyl group, -CH=N-R5, -S(O)n R6, -N(R7)R8, or -COR9, R3 is a hydrogen atom, a cya no group, a nitro group, an alkoxy group, a carboxyl group or an alkoxycarbonyl group, R4 is a hydrogen atom, or an alkyl group which m ay be substituted, R5 is an alkoxy group, or a pyridylmethyl group, R6 is an alkyl group which may be substituted, or an alkenyl group, each of R7 and R8 independently is a hydrogen atom, an alkyl group, an alkylsulfonyl group, a phenylsulfonyl group which may be substituted, a formyl group, an alkylcarbonyl group which may be substituted by a halogen atom, a cycloalkylcarbonyl group, or a benzoyl grou p which may be substituted, R9 is a hydrogen atom, an alkoxy group, a hydroxyl group, or an amino group which may be substituted, n is 0, 1 or 2, provided that when R2 is a hydrogen atom, an alkyl group or an alkoxy group, and Q is -CH2-, A is a furanyl group which may be substituted, a thienyl group which may be substituted, a pyridyl group which may be substituted, a pyridyl N-oxide group which may be substituted, or a thiazolyl group which may be substituted.