The mass spectra and the structure of prostaglandins E 9-enol trimethylsilyl ethers

Abstract

Enolsilylation of prostaglandins El and E, as well as their ll-desoxyanalogues and the corresponding methyl esters by a mixture of N,O-bis-(trimethylsi1yl)acetamide-piperidine (1 : 1) results in trimethylsilyl ether derivstives of Asc9)-enol forms contaminated by c.10% A9(lo'-en01 derivatives. Isomeric PGEl 9-enol-trimethylsilyl ether derivatives are separable by capillary gas-liquid chromatography and their mass spectra show different fragmentations of the side chains diagnostic for the above structures. Therefore, the use of 9-enol-trimethylsilyl ethers for prostaglandins E analysis in biological fluids could lead to formation of the two peaks in the gas chromatogram and moreover does not discriminate between common and 8-iso-prostaglandins E.