This invention provides compounds of the formula: wherein: X is a chemical bond, --CH.sub.2-- or --C(O)--; R.sub.1 is alkyl, cycloalkyl, --CH.sub.2-- cycloalkyl, pyridinyl, --CH.sub.2-pyridinyl, phenyl or benzyl; R.sub.2 is H, alkyl, cycloalkyl, --CH.sub.2-cycloalkyl, or perfluoroalkyl; R.sub.3 is H, halo, alkyl, perfluoroalkyl, alkoxy, cycloalkyl, --CH.sub.2-cycloalkyl, --NH.sub.2, or --NO.sub.2; R.sub.4 is optionally substituted phenyl, benzyl, benzyloxy, pyridinyl, or --CH.sub.2-pyridinyl, or the salt or ester forms thereof, as well as methods for using the compounds as inhibitors of plasminogen activator inhibitor-1 (PAI-1) and as therapeutic compositions for treating conditions resulting from fibrinolytic disorders such as deep vein thrombosis and coronary heart disease, and pulmonary fibrosis.