Tricyclic cephems as inhibitors of human leukocyte elastase. thieno[3,4-c]cepham sulfones and pyrrolo[3,4-c]cepham sulfones

Thieno- and pyrrolo[3,4-c]cepham sulfones were synthesized and compared to their furo analogs for activity as human leukocyte elastase inhibitors. Pyrrolo derivatives, especially when N-alkylated, combined excellent hydrolytic stability with remarkable inhibitory activity.