Structural identification of a novel degradant of the antibiotic pirlimycin formed under thermal stress conditions

✍ Scribed by Frank W. Crow; Wayne K. Duholke; Gary E. Martin; Richard F. Smith; Thomas J. Thamann; Anne M. Cooper; John W. Hallberg; James R. Blinn; Constance G. Chidestere

• Publisher: Journal of Heterocyclic Chemistry
• Year: 1999
• Tongue: English
• Weight: 529 KB
• Volume: 36
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570360436

✦ Synopsis

Abstract

The structure of a novel, thermally‐induced degradant of the antibiotic pirlimycin is presented. The degradant was discovered during thermal stress stability testing of pirlimycin. The structure was determined using high resolution mass spectrometry, ms/ms fragmentation, and extensive nmr studies including a combination of homonuclear TOCSY and gradient, inverse‐detected 2‐D nmr experiments which included GHSQC and GHMBC. All nmr, high resolution ms and ms/ms fragmentation data are consistent with loss of a molecule of HCl during a ring closure involving one of the hydroxyl moieties from the sugar portion of the molecule forming a tetrahydrofurano[3,2‐b]perhydropyran ring structure. The X‐ray crystal structure is reported for pirlimycin. Using this structure molecular modelling studies are performed which demonstrate the feasibility of the formation of the new structure.