The synthesis of 16(R)- or 16(S) -methylprostaglandins

Design and synthesis of a selective EP4-receptor agonist. Part 1: discovery of 3,7-dithiaPGE1 derivatives and identification of their omega chains

Improvement of EP4-receptor selectivity and the agonist activity by introduction of heteroatoms into the alpha chain of PGE1 was investigated. Among the compounds tested, 3,7-dithiaPGE1 4a exhibited good EP4-receptor selectivity and agonist activity. Further modification of the omega chain of 3,7-dithiaPGE1 was performed to improve EP4-receptor selectivity and agonist activity. Of the compounds produced, 16-phenyl-omega-tetranor-3,7-dithiaPGE1 4p possessing moderate EP4-receptor selectivity and agonist activity, was identified as a new chemical lead for further optimization by modification of the aromatic moiety.

Metabolism of prostaglandin glycerol esters and prostaglandin ethanolamides in vitro and in vivo

Prostaglandin glycerol esters (PG-Gs) and prostaglandin ethanolamides (PG-EAs) are generated by the action of cyclooxygenase-2 on the endocannabinoids 2-arachidonylglycerol (2-AG) and arachidonylethanolamide, respectively. These novel eicosanoids may have unique pharmacological properties and/or serve as latent sources of prostaglandins at sites remote from their tissue of origin. Therefore, we investigated the metabolism of PG-Gs and PG-EAs in vitro and in vivo. PGE(2)-G was rapidly hydrolyzed in rat plasma to generate PGE(2) (t(1/2) = 14 s) but was only slowly metabolized in human plasma (t(1/2) > 10 min). An intermediate extent of metabolism of PGE(2)-G was observed in human whole blood (t(1/2) approximately 7 min). The parent arachidonylglycerol, 2-AG, and the more stable regioisomer, 1-AG, also were much more rapidly metabolized in rat plasma compared with human plasma. PGE(2)-EA was not significantly hydrolyzed in plasma, undergoing slow dehydration/isomerization to PGB(2)-EA. Both PGE(2)-G and PGE(2)-EA were stable in canine, bovine, and human cerebrospinal fluid. Human 15-hydroxyprostaglandin dehydrogenase, the enzyme responsible for the initial step in PG inactivation in vivo, oxidized both PGE(2)-G and PGE(2)-EA less efficiently than the free acid. The sterically hindered glyceryl prostaglandin was the poorest substrate examined in the E series. Minimal 15-hydroxyprostaglandin dehydrogenase oxidation of PGF(2 alpha)-G was observed. PGE(2)-G and PGE(2)-EA pharmacokinetics were assessed in rats. PGE(2)-G was not detected in plasma 5 min following an intravenous dose of 2 mg/kg. However, PGE(2)-EA was detectable up to 2 h following an identical dose, displaying a large apparent volume of distribution and a half-life of over 6 min. The results suggest that endocannabinoid-derived PG-like compounds may be sufficiently stable in humans to exert actions systemically. Furthermore, these results suggest that the rat is not an adequate model for investigating the biological activities of 2-arachidonylglycerol or glyceryl prostaglandins in humans.

Synthesis and biological properties of 16(S)-amino-PGF2 alpha methyl ester

A synthesis of 16-amino-derivatives of PGF2 alpha is reported. Introduction of an amino group into position 16 of PGF2 alpha has decreased the sensitivity of the compound to metabolic degradation. 16(S)-amino-PGF2 alpha methyl ester shows high abortifacient activity with reduced diarrhoeic side effect.

Prostaglandins and congeners XIII (1). The synthesis of dl-erythro-16-methoxyprostaglandins

dl-Erythro-16-methoxy-PGE2, PGA2, PGF2alpha, 11-deoxy PGE1, and 11-deoxy PGF1alpha have been prepared via the cuprate conjugate addition procedure. These congeners are less potent than the parent prostaglandins as stimulators of isolated gerbil colon contractions and as bronchodilators in the guinea pig Konzett assay.