2,4,5-Triphenylisothiazol-3(2H)-one 1,1-dioxides as inhibitors of human leukocyte elastase.

Abstract

A series of substituted 2,4,5-triphenylisothiazol-3(2H)-one 1,1-dioxides 9 was synthesized and investigated as inhibitors of human leukocyte elastase (HLE). All compounds were found to inhibit HLE in a time-dependent manner and most of them exhibited kobs/[I] values > 300 M− 1s− 1. The most potent 3-oxosultam of this series was 9l (kobs/[I] = 2440 M− 1s− 1). Kinetic investigations performed with 9g and different substrate concentrations did not allow to clearly distinguish between a competitive or noncompetitive mode of inhibition. A more complex interaction is supported by the failure of a linear dependency of kobs values on the inhibitor concentration.