##STR00001## Heterocyclic compounds represented by the general formula (I) and having elastase inhibiting activity; and intermediates for the synthesis thereof: (I) wherein R.sup.1 is a heterocyclic group represented by the general formula (II): (II) [wherein A represents the presence or absence of a benzene ring; X is oxygen, sulfur or NH; and Y is nitrogen or CH], and the heterocyclic group may be substituted with one to three substituents which may be the same or different and are selected from the group consisting of lower alkyl, lower alkoxy, and phenyl which may be substituted with optionally halogenated lower alkyl, lower alkoxy or halogeno; and R.sup.2 and R.sup.3 are each hydrogen or hydroxyl, or R.sup.2 and R.sup.3 may be united to form an oxo group, with the proviso that both are not hydrogen.