- Adjuvant properties of a simplified C32 monomycolyl glycerol analogue
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A simplified C32 monomycolyl glycerol (MMG) analogue demonstrated enhanced immunostimulatory activity in a dioctadecyl ammonium bromide (DDA)/Ag85B-ESAT-6 formulation. Elevated levels of IFN-γ and IL-6 were produced in spleen cells from mice immunised with a C32 MMG analogue comparable activity to the potent Th1 adjuvant, trehalose 6,6′-di-behenate (TDB).
- Bhowruth, Veemal,Minnikin, David E.,Agger, Else Marie,Andersen, Peter,Bramwell, Vincent W.,Perrie, Yvonne,Besra, Gurdyal S.
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scheme or table
p. 2029 - 2032
(2009/12/03)
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- An improved synthesis of trehalose 6-mono- and 6,6'-di-corynomycolates and related esters
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A simplified synthesis of 6-mono- and 6,6'-di-corynomycolate esters of α,α-trehalose, and related compounds, was achieved by coupling the (hydroxyl-protected) acids to the partially trimethylsilylated sugar in the presence of dicyclohexylcarbodiimide and 4-dimethylaminopyridine.As acid reactants, (2-RS,3-RS)-3-hydroxy-2-tetradecyloctadecanoic acid (DL-corynomycolic acid) and its 2RS, 3SR diastereomer were prepared from methyl palmitate by sequential Claisen condensation, reduction, chromatographic separation, and saponification.Reaction with tert-butylchlorodimethylsilane (imidazole) gave the disubstituted ether-esters, which were converted into the required 3-tert-butyldimethylsilyl ethers by partial hydrolysis. 6-Linked monocorynomycolate was obtained in excellent yield (78percent) from the reaction of the RS,SR acid with the known heptakis-O-(trimethylsilyl)trehalose, and in good yield from equimolar portions of RS,RS acid and hexakis-O-(trimethylsilyl)trehalose.An excess (2.5-molar portions) of the RS,RS acid gave the 6,6'-diester (69percent).The mono- and di-palmitate were similarly obtained from (Me3Si)6-trehalose.The mono (RS,RS)-(Me3Si)6-trehalose coupling product was partially resolved on a silica gel column into its RR and SS diastereomers, the former corresponding to the naturally occurring trehalose monocorynomycolate.All coupling products were deprotected to free trehalose esters by treatment first with K2CO3 in methanol, then tetrabutylammonium fluoride-trifluoracetic acid in oxolane.
- Datta, Arun K.,Takayama, Kuni,Nashed, Mina A.,Anderson, Laurens
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- Acyclic Stereoselection. 17. Simple Diastereoselection in the Addition of Medium- and Long-Chain n-Alkyl Ketone Lithium Enolates to Aldehydes
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The n-alkyl tert-butyl ketones 1b-d have been prepared and the stereochemistry of their aldol reaction with benzaldehyde has been investigated.As with ketone 1a, ketones 1b-d give Z-enolates that react with benzaldehyde in THF at -78 deg C to give syn aldols.When the aldol additions are carried out in pentane, the syn aldols are also the kinetic products, but syn-anti equilibration is much more rapid in this solvent; after reaction at 25 deg C for 20 min, ketones 1c and 1d give only the anti aldols 3c and 3d.Aldolate syn-anti equilibration becomes more facile as the size of the α-alkyl group increases.Ketone 14 has been prepared and employed in a synthesis of methyl (+/-)-isocorynomycolate; the crucial aldol addition, leading to β-hydroxyketones 15 and 16, proceeds with kinetic stereoselection of only 4.5:1.
- Heathcock, , Clayton H.,Lampe, John
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p. 4330 - 4337
(2007/10/02)
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