Fused heterocyclic derivative, medicinal composition containing the same, and medicinal use thereof

A fused heterocyclic derivative of the general formula (I):

• wherein ring A is a thiophene ring;
• RAis a halogen atom, a cyano group, a nitro group, an optionally substituted lower alkyl group, an optionally substituted lower alkenyl group, an optionally substituted lower alkynyl group, a hydroxyiminomethyl group, an optionally substituted (lower alkyl)sulfonyl group, an optionally substituted (lower alkyl)sulfinyl group, a tetrazolyl group, OW1, SW1, COW1, COOW1, NHCOW1, NHCONW2W3, NW2W3, CONW2W3 or SO2NW2W3 in which W1 to W3 independently are a hydrogen atom or an optionally substituted lower alkyl group, or W2 and W3 may bind together with the neighboring nitrogen atom to form an optionally substituted cyclic amino group;
• m is an integer number of 0 to 3;
• ring B is aryl or a monocyclic heteroaryl group;
• RB is a halogen atom, a cyano group, an optionally substituted lower alkyl group, OW4, COW4, COOW4 or CONW5W6 in which W4 to W6 independently are a hydrogen atom or an optionally substituted lower alkyl group, or W5 and W6 may bind together with the neighboring nitrogen atom to form an optionally substituted cyclic amino group;
• n is an integer number of 0 to 2;
• El is an oxygen atom;
• E2 is an oxygen atom;
• U is a single bond;
• X is a group of —S—L—Y, —O—L—Y, —CO—L—Y, or —SO2—L—Y in which L is an optionally substituted lower alkylene group;
• Y is a group of Z or —NW7W8 wherein W7 and W8 independently are a hydrogen atom, an optionally substituted lower alkyl group or Z with the proviso that W7 and W8 are not hydrogen atoms at the same time, or W7 and W8 may bind together with the neighboring nitrogen atom to form an optionally substituted cyclic amino group;
• Z is an optionally fused and optionally substituted cycloalkyl group, an optionally fused and optionally substituted heterocycloalkyl group, an optionally fused and optionally substituted aryl group or an optionally fused and optionally substituted heteroaryl group;
• or a pharmaceutically acceptable salt thereof.