| abstract |
An excellent method for efficiently producing a benzofuran derivative or a pyridofuran derivative, or a pharmaceutically acceptable salt of any of these, the derivatives being represented by the general formula [I] (see formula (I)): (where X represents -N = or -CH =; R1 represents hydrogen, halogen, lower alkyl, lower alkoxy, cyano or amino optionally substituted by lower alkyl; ring A represents a nitrogen heterocyclic group; ring B represents a benzene ring or pyridine ring optionally substituted; and R3 represents hydrogen or lower alkyl); derivatives are useful as an inhibitor against an activated blood clotting factor X. |