Compounds having the structural formula ##STR1## wherein L is N, O or SO.sub.n wherein n is 0, 1 or 2;L--R.sup.1 is a leaving group, H--L--R.sup.1 is the conjugate acid thereof and,when L is N, H--L--R.sup.1 has a pK.sub.a value less than or equal to 6, when L is O, H--L--R.sup.1 has a pK.sub.a value less than or equal to to 8, and when L is SO.sub.n, H--L--R.sup.1 has a pK.sub.a value less than or equal to 5;R.sup.2 is primary or secondary alkyl of two to four carbon atoms, primary alkylamino of one to three carbon atoms, primary alkylmethylamino of two to four carbon atoms, diethylamino or primary alkoxy of one to three carbon atoms; andR.sup.3 is from one to three of a variety of substituents at any or all of the 5-, 6- and 7-positions;or a pharmaceutically acceptable acid addition salt thereof if the compound has a basic functional group or a pharmaceutically acceptable base addition salt thereof if the compound has an acidic functional group,which inhibit the enzymatic activity of proteolytic enzymes, and processes for preparation thereof, method of use thereof in treatment of degenerative diseases and pharmaceutical compositions thereof are disclosed.