| 摘要 |
NEW MATERIAL:The compound of formula I [R<1> is H or 1-5C alkyl; R<2>-R<4> are H, 1-5C alkoxy or OH; two of R<2>-R<4> may together form the group of formula IV or formula V; X is O, S or NR<5> (R<5>=R<1>); n is 1-4; dotted line shows that the bond between the 4- and 5-carbon atoms of the pyridazinone ring is single bond or double bond] or its salt. USE:A medicine. A cardiotonic agent. It can be administered orally or parenterally at a dose of 0.1-10mg/kg body weight daily in the case of oral administration. PREPARATION:The compound of formula I can be produced e.g. by reacting a carboxylic acid of formula II with an alkyl halocarboxylate in a mixed solvent consisting of N,N-dimethylformamide and tetrahydrofuran, etc., at -20-+100 deg.C for 5-10hr in the presence of a basic compound such as triethylamine and reacting the resultant mixed acid anhydride with an amine of formula III at -20-+100 deg.C for 5min-10hr.
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