3-(substituted propylidene)-2-azetidinone derivates for blood platelet aggregation

A 2-azetizinone derivative represented by the formula ##STR11## wherein R.sup.1 is a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an alkoxycarbonyl group in which the alkoxy group has 1 to 4 carbon atoms, R.sup.2 is a group represented by the formula ##STR12## (wherein R.sup.3 and R.sup.4 are the same or different and are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 3 to 5 carbon atoms, a phenyl group or a benzyl group), a group represented by the formula ##STR13## wherein R.sup.5 is a hydrogen atom, a phenyl group substituted by a halogen atom or an alkoxy group having 1 to 4 carbon atoms, a phenyl group, an alkyl group having 1 to 4 carbon atoms or a pyridyl group), a group represented by the formula ##STR14## (wherein R.sup.6 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a benzyl group, and R.sup.7 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), a group represented by the formula ##STR15## (wherein R.sup.8 and R.sup.9 are the same or different and each a hydrogen atom or an alkyl group having 1 to 4 carbon atom), a pyrrolidinyl group or a tetrahydroazepinyl group, and n is an integer of from 2 to 10), and a salt thereof.