Indole derivatives with antiviral activity

A compound of the formula:

• wherein
• R1 is hydrogen, lower alkyl, cycloalkyl lower alkyl, lower alkylsulfonyl, lower alkylcarbonyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted arylcarbonyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaralkyl, substituted or unsubstituted heteroarylsulfonyl, lower alkoxycarbonyl, substituted or unsubstituted sulfamoyl, or substituted or unsubstituted carbamoyl;
• R2 is hydrogen, lower alkyl, lower alkylcarbonyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, substituted or unsubstituted arylcarbonyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroaralkyl, substituted or unsubstituted arylthio, substituted or unsubstituted arylsulfinyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted heterocyclyl lower alkyl, or substituted or unsubstituted heterocyclyl sulfonyl;
• R3, R4, R5, and R6 each is independently hydrogen, halogen, trihalogenated lower alkyl, hydroxy, lower alkoxy, nitro, amino, esterified or unesterified carboxy, substituted or unsubstituted aralkyloxy, or substituted or unsubstituted arylsulfonyloxy;
• X is hydroxy or substituted or unsubstituted amino;
• Y is COOH, an ester, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl,
• provided that a compound wherein R1, R2, R3, R5, and R6 each is hydrogen;
• R4 is hydrogen, methoxy, or chloro;
• X is hydroxy;
• and Y is COOC2H5 is excluded,
• a tautomer, or a pharmaceutically acceptable salt, or a hydrate thereof.