Nitrogen—containing heterocyclic derivatives having 2,6-disubstituted styryl

A nitrogen-containing heterocyclic derivative represented by formula (I) below:

• wherein symbols in formula (I) above have the following significance:
• R1 and R2 represent H—;
• R3 and R4, which may be the same or different, represent a lower alkyl;
• R5 and R6 represent H—;
• R9 represents an optionally substituted acyl, wherein the optionally substituted acyl is an optionally substituted morpholin-4-ylmethylcarbonyl, an optionally substituted 1,4-oxazepan-4-ylmethylcarbonyl, or an optionally substituted piperidin-1-ylmethylcarbonyl, and wherein the substitutent in the optionally substituted acyl is at least one substituent selected from:
• R101R102N, wherein R101 and R102 represent H;
• a lower alkyl which may optionally be substituted with OH;
• and H2N—CO—;
• R10, R11, R12 and R13 represent H—;
• A represents piperidin-4-yl;
• n represents 0, or a pharmaceutically acceptable salt thereof.