Heterocyclic prostaglandin analogues. Part 4. Piperazine-2,5-diones, pyrazolidine-3,5-diones, 1,2,4-triazolidinediones, 1,3,4-oxadiazolidinediones and 1,3,4-thiadiazolidinediones

Abstract

Piperazinedione prostaglandin analogues (10) have been prepared from the previously described di-substituted glycine esters (8). The corresponding pyrazolidinediones (27) and triazolidinediones (30) were obtained by multi-step synthesis from ethyl carbazate (19)via the common intermediates (23). An oxadiazolidinedione (37) and a thiadiazolidinedione (40b) are also described. The piperazinedione (10c) and the triazolidinedione (30c) have ca. one-tenth of the anti-aggregatory potency of prostaglandin E₁. Some structure–activity relationships have emerged.