### API-Mass Spectrometry of Polyketides. IIAPI-Mass Spectrometry of Polyketides. II

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 Author Ashley, Gary W. ♦ Carney, John R. Source J-STAGE Content type Text Publisher JAPAN ANTIBIOTICS RESEARCH ASSOCIATION Language English
 Abstract The API-MS spectra of 6-deoxyerythronolide B (6-dEB) and a number of its analogs have been studied to gain information into the fragmentation patterns of 6-deoxyerythronolides under atmospheric pressure ionization conditions. The API-MS spectrum of 6-dEB shows five major families of fragments. The spectra of a series of desmethyl-6-dEBs allow assignment of these fragment families to structural subunits as well as provide information regarding the fragmentation mechanisms. The spectrum of $[9-^{18}O]-6-dEB$ is consistent with loss of the ketone oxygen during the first dehydration, and the spectra of other oxygen-modified analogs implicate the non-obligate formation of a 5, 9-hemiacetal in the initial stages of fragmentation. These results taken together are used to propose a model for the fragmentation of 6-dEB and its analogs under API conditions. ISSN 00218820 Learning Resource Type Article Publisher Date 2004-09-25 e-ISSN 18811469 Journal The Journal of Antibiotics(antibiotics1968) Volume Number 57 Issue Number 9 Page Count 11 Starting Page 579 Ending Page 589