Thiazolylbenzofuran derivatives and pharmaceutical composition comprising the same

A compound of the formula:

• ##STR6## wherein R.sup.1 is lower alkyl optionally substituted with halogen, lower alkylamino or lower alkyl(acyl)amino;
• cyclo(lower)alkyl;
• tricycloalkyl;
• aryl optionally substituted with lower alkoxy;
• thienyl;
• or pyridyl;
• R.sup.2 is hydrogen or halogen, or
• R.sup.1 and R.sup.2 are taken together with the adjacent atoms to form cycloalken ring or tetrahydroazepine optionally substituted with acyl,
• R.sup.3 is hydrogen, halogen, hydroxy, lower alkyl or lower alkoxy,
• R.sup.4 is hydrogen;
• acyl;
• cyano;
• aryl optionally substituted with hydroxy(lower)alkyl, halo(lower)alkyl, cyano(lower)alkyl, tetrazolyl(lower)alkyl or acyl;
• or lower alkyl which may be substituted with substituent(s) selected from the group consisting of halogen, cyano, hydroxy, lower alkylsulfonyloxy, arylsulfonyloxy, acyl, acyl(lower)alkylthio and aryl optionally substituted with halo(lower)alkyl, cyano(lower)alkyl, tetrazolyl(lower)alkyl, cyano, acyl, acyl(lower)alkyl, tetrazolyl or (lower alkylsulfinyl)(lower alkylthio)lower alkenyl;
• wherein in R.sup.1, R.sup.1 and R.sup.2 taken together, and R.sup.4 acyl is selected from the group consisting of carboxy, esterified carboxy, carbamoyl optionally substituted with lower alkyl arylsulfonyl, lower alkylsulfonyl, lower alkanoyl, aroyl and heterocycliccarbonyl,
• A is lower alkylene, lower alkenylene or a single bond,
• X is a single bond, O or S, and
• Y is O or S,
• provided that A or X is not a single bond when R.sup.1 is lower alkyl or aryl and R.sup.2 is hydrogen, or pharmaceutically acceptable salts thereof.