Synthesis of thiaprostaglandin E1 derivatives

Design and synthesis of a selective EP4-receptor agonist. Part 4: practical synthesis and biological evaluation of a novel highly selective EP4-receptor agonist

A practical method of synthesizing a highly selective EP4-receptor agonist 1 using Corey lactone 2 as a key intermediate was developed. Selective methanesulfonylation of the primary alcohol of the diol 8 under the newly devised conditions followed by the protection of the remaining secondary alcohol are key reactions in this new method. Further biological evaluation of 1a-b is also reported.

Design and synthesis of a highly selective EP4-receptor agonist. Part 2: 5-thia and 9beta-haloPG derivatives with improved stability

Further chemical modification to identify more chemically stabilized EP4-receptor selective agonists was continued. As a result, a further two EP4-receptor selective agonists 5-thiaPGE(1) 2a, 10 and 9beta-chloroPGF(2) analogue 11 were discovered.

Dehydration and epimerization of 7-thiaprostaglandin E1 analogues

The kinetics of epimerization and dehydration of 7-thiaprostaglandin E1 (7-S-PGE1) analogues in various solvent systems were examined using HPLC. The epimerization at the C-8 position was rapid and resulted in a considerable amount of the 8-epimer (14-35%) at equilibrium. The dehydration was also rapid compared with that of the natural prostaglandin E1 (PGE1). The lability may be attributed to an effect of the sulfur atom substituted for the C-7 methylene.