- Structural confirmation of the dihydrosphinganine and fatty acid constituents of the dental pathogen Porphyromonas gingivalis
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Porphyromonas gingivalis, a recognized periodontal pathogen, is a source of sphinganine bases, fatty acids, free ceramides as well as complex lipids that potentiate interleukin-1b-mediated secretory responses in gingival fibroblasts. The purpose of this study is the structural verification of the sphinganine bases and fatty acids that had been proposed as major components of the complex lipids found in P. gingivalis. The putative C17, C18, and C19 sphinganine bases were prepared from Garner's aldehyde (1) or from a protected serine Weinreb's amide (2). We confirmed that isobranched sphinganine bases are the major structural feature of the ceramides observed from P. gingivalis. We also prepared a C17 unsaturated fatty acid, along with an isobranched C17 3-hydroxy fatty acid, and determined that the major component of the active lipids was the latter. The Royal Society of Chemistry 2007.
- Mun, JiYoung,Onorato, Amber,Nichols, Frank C.,Morton, Martha D.,Saleh, Abdullah I.,Welzel, Morgan,Smith, Michael B.
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p. 3826 - 3833
(2008/10/09)
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- The syntheses of cyclic spermine alkaloids: Analogues of buchnerine and budmunchiamine C
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The syntheses of two macrocyclic spermine alkaloids, analogues 1 and 2 of budmunchiamine C and buchnerine, in which N,N′-bis(2-aminoethyl)hexane-1,6-diamine (PA 262; 4) replaces spermine as polyamine backbone, were accomplished by two different methods. The first synthetic approach was based on a metal-template intramolecular amidation of tetraamino esters prepared from a Michael addition of protected PA 262 10 to ethyl hexadec-2-ynoate (12) and ethyl prop-2-ynoate 17. respectively (see Schemes 4 and 5. resp.). The consecutive Michael addition of ethane-1,2-diamine to unsaturated esters and aminolysis was employed in the second synthetic approach to prepare the precursors 23 and 24 (Scheme 6). The macrocyclic lactams were then constructed by macrocyclization of sulfonamido derivatives 25 and 26 in DMF with Cs2CO3 as catalyst.
- Li, Yi,Hesse, Manfred
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p. 310 - 323
(2007/10/03)
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- Synthesis and immobilization of ceramide analogs on silica particles
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Ceramides are the major lipid components of the stratum corneum, the major permeability barrier of the skin. Here we report a chemical synthesis of ceramide analogs covalently bonded on the silica particles, that can be used to predict the skin permeability of chemicals via HPLC methods.
- Yin, Jianming,Liu, Hanlan,Pidgeon, Charles
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p. 179 - 182
(2007/10/03)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (II). -PHOTOLYSIS OF UNSYMMETRICAL DIACYLPEROXIDES WITH ALKENYL-, HALO-, KETO-, CARBOXYL-GROUPS AND A CHIRAL α-CARBON. COMPARISON WITH THE MIXED KOLBE ELECTROLYSIS.
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- Alkenoyl and functionalized alkanoyl dodecanoyl peroxides are prepared in 70 to 97 percent yield and photolyzed at -78 deg C.Thereby 4- to 10-alkenoyl and 4-alkynoyl peroxides afford good yields (56 - 68 percent) of unsymmetrical coupling products.Similarly α- to δ-haloalkanoyl, cholanoyl or 3- and 4-carboxyalkanoyl peroxides can be coupled (40 - 70 percent).The α-chiral diacyl peroxide 1s undergoes the photochemical coupling reaction with 80 percent retention of its configuration.The photolysis of diacyl peroxides at -78 deg C proves to be a favorable supplement of the Kolbe-electrolysis in cases, where the electrolysis fails or produces low yields.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4213 - 4236
(2007/10/02)
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