HETEROCYCLIC COMPOUNDS, INTERMEDIATES THEREOF AND ELASTASE INHIBITORS

摘要

Heterocyclic compounds represented by general formula (I-a), its esters or salts thereof; and human neutrophilic elastase inhibitors, etc. containing t he same as the active ingredient wherein A and B are the same of different and each represents lower alkylene optionally substituted by oxo; D represents a monocyclic or dicyclic heterocyclic group optionally substituted by oxo; R1 and R2 are the same or different and each represents lower alkyl; R3 and R4 are different from each other and each represents hydrogen or hydroxy, or R3 and R4 form together oxo; and R5 represents 2-benzoxasolyl, trifluoromethyl, benzylaminocarbonyle, etc.