Synthesis and Mass Spectral Characterization of Mycobacterial Phosphatidylinositol and Its Dimannosides

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• 作者：Gregory M. Rankin ; Benjamin J. Compton ; Karen A. Johnston ; Colin M. Hayman ; Gavin F. Painter ; David S. Larsen
• 刊名：The Journal of Organic Chemistry
• 出版年：2012
• 出版时间：August 17, 2012
• 年：2012
• 卷：77
• 期：16
• 页码：6743-6759
• 全文大小：544K
• 年卷期：v.77,no.16(August 17, 2012)
• ISSN：1520-6904

文摘

A family of naturally occurring mycobacterial phosphatidylinositol (PI) and its dimannosides (PIM₂, AcPIM₂, and Ac₂PIM₂) that all possess the predominant natural 19:0/16:0 phosphatidyl acylation pattern were prepared to study their mass spectral fragmentations. Among these, the first synthesis of a fully lipidated PIM (i.e., (16:0,18:0)(19:0/16:0)-PIM₂) was achieved from (卤)-1,2:4,5-diisopropylidene-d-myo-inositol in 16 steps in 3% overall yield. A key feature of the strategy was extending the utility of the p-(3,4-dimethoxyphenyl)benzyl protecting group for its use at the O-3 position of inositol to allow installation of the stearoyl residue at a late stage in the synthesis. Mass spectral studies were performed on the synthetic PIMs and compared to those reported for natural PIMs identified from a lipid extract of M. bovis BCG. These analyses confirm that fragmentation patterns can be used to identify the structures of specific PIMs from the cell wall lipid extract.