Transformation of Cloprostenol into E-Type Derivatives and a Comparative Study of Their Uterotonic Activity.

The racemic methyl ester of 16-(m-chlorophenoxy)-17,18,19,20-tetranorprostaglandin F2α (cloprostenol) was transformed into corresponding E-type derivatives through the stages of selective protection of the C-11 and C-15 hydroxyls as tert-butyldiphenylsilyl ethers, oxidation of the C-9 alcohol, removal of the protecting silyl groups, and enzymatic hydrolysis of the methyl ester. The E-type acid and corresponding methyl ester thus obtained were tested for uterotonic activity. The results were compared with the activity of the parent cloprostenol and corresponding methyl ester. The E-type prostaglandin methyl ester doubled (p > 0.05) the frequency of contractions of the rat uterine horn compared to the control and appeared to be more effective than the E-type acid and misoprostol (p < 0.05). [ABSTRACT FROM AUTHOR]