4,5,8,9‐tetrahydro‐8‐methyl‐9‐oxothieno[3′,2′:5,6]cyclohepta[1,2‐b]‐ pyrrole‐7‐acetic acid. A new anti‐inflammatory/analgesic agent

Abstract

AbstractThe synthesis of the thienocyclohepta[1, 2‐b]pyrrole acid 1 from the morpholide 3 is reported. This novel morpholide was prepared by regiospecific alkylation of the dianion of 4‐(1, 3‐dioxobutyl)morpholine with 3‐bromomethylthiophene. Subsequent Knorr pyrrole synthesis led to the morpholide 8b which was converted to the desired tricyclic ring system under Vilsmeier conditions. An alternative route involving Friedel‐Crafts cyclisation was used to prepare the related benzocycloheptapyrrole 2.