The structure of leptosphaerin

✍ Scribed by Guy A Schiehser; James D White; Gayle Matsumoto; John O Pezzanite; Jon Clardy

• Book ID: 104219351
• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 161 KB
• Volume: 27
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85272-7

✦ Synopsis

The structure and relative configuration of leptosphaerin, a metabolite of the marine ascomycete Leptosphaeria oraemaris (Linder) was established as 2 by spectral analysis and elimination of an alternative structure I through synthesis.

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Previous studies have led to the isolation and identification of several metabolites from the marine ascomycete Leptosphaeria oraemaris (Linder). I Further examination of extracts of L. oraemaris grown in liquid culture afforded a new crystalline substance (mp 189.5-190.5°C, CsHIINO 2) which we have named leptosphaerin.

The ultraviolet spectrum of leptosphaerin (Xma x 246 rim), in combination with its iH NMR spectrum which displayed a one-proton signal at S 7.51, suggested an eB-unsaturated carbonyl chromophore bearing a B hydrogen. The NMR spectrum also revealed that three exchangeable protons were present, while the infrared spectrum gave evidence for both OH and NH groups.

The nature of the hydroxyl functions was made clear when the NMR spectrum of leptosphaerin was /~..~ Y'-,,I~ CH3 H 0 1 X=NH,