Mass spectra of prostaglandins: II. Trimethylsilyl and alkyloxime-trimethylsilyl derivatives of prostaglandins B1 and B2.

The mass spectra of the trimethylsilyl ester trimethylsilyl ether derivatives of prostaglandins B1 and B2, and of theirO-ethyl andO-methyl oximes are reported and discussed. The high resolution spectra of these compounds are also considered. These spectra are compared with those of the correspondingd 9-trimethylsilyl derivatives and of the selectively labeled trimethylsilyl esterd 9-trimethylsilyl ethers. The base peaks of the spectra of the trimethylsilyl derivatives are formed by sequential loss of C5H11 (by cleavage of C-15/6) and of CO (from the ring). The spectra of the oxime-trimethylsilyl derivatives are dominated by ions resulting from loss of the alkoxy group of the oxime moiety.