Synthesis of new thiazinoindole derivatives and their evaluation as inhibitors of human leukocyte elastase and other related serine proteases

Abstract

A novel thiazinoindole tricyclic ring system was designed as potential inhibitors of serine proteases. The compounds were synthesized by ring closure at 80–90°C in poliphosphoric acid of the appropriate N′-alkyl or aryl substituted indolylthiourea derivatives. Members of this class of compounds inhibited human leukocyte elastase (K i=30–40 μM) and α-chymotrypsin.